[REL] v2.1.0

This commit adds the devtools as a zip file containing both chrome
and firefox versions of the extension in the release and also updates
the doc to install it easily.

.eslintrc

@@ -0,0 +1,47 @@
+{
+    "env": {
+        "browser": true,
+        "node": true,
+        "es2022": true
+    },
+    "parser": "@typescript-eslint/parser",
+    "plugins": ["@typescript-eslint"],
+    "parserOptions": {
+        "sourceType": "module"
+    },
+    "root": true,
+    "rules": {
+        "no-restricted-globals": ["error", "event", "self"],
+        "no-const-assign": ["error"],
+        "no-debugger": ["error"],
+        "no-dupe-class-members": ["error"],
+        "no-dupe-keys": ["error"],
+        "no-dupe-args": ["error"],
+        "no-dupe-else-if": ["error"],
+        "no-unsafe-negation": ["error"],
+        "no-duplicate-imports": ["error"],
+        "valid-typeof": ["error"],
+        "@typescript-eslint/no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": false, "caughtErrors": "all" }],
+        "no-restricted-syntax": [
+            "error",
+            {
+                "selector": "MemberExpression[object.name='test'][property.name='only']",
+                "message": "test.only(...) is forbidden",
+            },
+            {
+                "selector": "MemberExpression[object.name='describe'][property.name='only']",
+                "message": "describe.only(...) is forbidden",
+            }
+        ],
+    },
+    "globals": {
+        "describe": true,
+        "expect": true,
+        "test": true,
+        "beforeEach": true,
+        "beforeAll": true,
+        "afterEach": true,
+        "afterAll": true,
+        "jest": true,
+    },
+}

.github/workflows/deploy.yml

@@ -22,7 +22,8 @@ jobs:
       uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
-    - run: npm install
+    - run: npm ci
     - run: npm run test
     - run: npm run check-formatting
+    - run: npm run lint
     - run: npm run build

.gitignore

@@ -14,9 +14,6 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 
-package-lock.json
-yarn.lock
-
 #ide's
 .vscode
 .idea
@@ -31,4 +28,4 @@ release-notes.md
 .rpt2_cache
 
 # useful in some cases
-/temp
+/temp

README.md

@@ -93,6 +93,7 @@ Are you new to Owl? This is the place to start!
 - [Loading Templates](doc/reference/app.md#loading-templates)
 - [Mounting a component](doc/reference/app.md#mount-helper)
 - [Portal](doc/reference/portal.md)
+- [Precompiling templates](doc/reference/precompiling_templates.md)
 - [Props](doc/reference/props.md)
 - [Props Validation](doc/reference/props.md#props-validation)
 - [Reactivity](doc/reference/reactivity.md)
@@ -112,6 +113,7 @@ Are you new to Owl? This is the place to start!
 - [Why did Odoo build Owl?](doc/miscellaneous/why_owl.md)
 - [Changelog (from owl 1.x to 2.x)](CHANGELOG.md)
 - [Notes on compiled templates](doc/miscellaneous/compiled_template.md)
+- [Owl devtools extension](doc/tools/devtools.md)
 
 ## Installing Owl
 
@@ -120,8 +122,28 @@ Owl is available on `npm` and can be installed with the following command:
 ```
 npm install @odoo/owl
 ```
-
 If you want to use a simple `<script>` tag, the last release can be downloaded here:
 
-- [owl-1.4.10](https://github.com/odoo/owl/releases/tag/v1.4.10)
+- [owl](https://github.com/odoo/owl/releases/latest)
+
+## Installing Owl devtools
+
+The Owl devtools browser extension is also available in the [release](https://github.com/odoo/owl/releases/latest):
+Unzip the owl-devtools.zip file and follow the instructions depending on your browser:
+
+### Chrome
+
+Go to your chrome extensions admin panel, activate developer mode and click on `Load unpacked`.
+Select the devtools-chrome folder and that's it, your extension is active! 
+There is a convenient refresh button on the extension card (still on the same admin page) to update your code. 
+Do note that if you got some problems, you may need to completly remove and reload the extension to completly refresh the extension.
+
+### Firefox 
+Go to the address about:debugging#/runtime/this-firefox and click on `Load temporary Add-on...`.
+Select any file in the devtools-firefox folder and that's it, your extension is active! 
+Here, you can use the reload button to refresh the extension.
+
+Note that you may have to open another window or reload your tab to see the extension working.
+Also note that the extension will only be active on pages that have a sufficient version of owl.
+
 

doc/learning/tutorial_todoapp.md

@@ -174,9 +174,9 @@ class Root extends Component {
 ```
 
 The template contains a [`t-foreach`](../reference/templates.md#loops) loop to iterate
-through the tasks. It can find the `tasks` list from the component, since the
-component is the rendering context. Note that we use the `id` of each task as a
-`t-key`, which is very common. There are two css classes: `task-list` and `task`,
+through the tasks. It can find the `tasks` list from the component, since the rendering
+context contains the properties of the component. Note that we use the `id` of each task
+as a `t-key`, which is very common. There are two css classes: `task-list` and `task`,
 that we will use in the next section.
 
 Finally, notice the use of the `t-att-checked` attribute:
@@ -240,7 +240,7 @@ class Task extends Component {
   static template = xml /* xml */`
     <div class="task" t-att-class="props.task.isCompleted ? 'done' : ''">
       <input type="checkbox" t-att-checked="props.task.isCompleted"/>
-      <span><t t-esc="props.task.title"/></span>
+      <span><t t-esc="props.task.text"/></span>
     </div>`;
   static props = ["task"];
 }
@@ -502,6 +502,10 @@ deleteTask(task) {
 Notice that the `onDelete` prop is defined with a `.bind` suffix: this is a special
 suffix that makes sure the function callback is bound to the component.
 
+Notice also that we have two functions named `deleteTask`. The one in the Task
+component just delegates the work to the Root component that owns the task list
+via the `onDelete` property.
+
 ## 10. Using a store
 
 Looking at the code, it is apparent that all the code handling tasks is scattered
@@ -743,7 +747,7 @@ the user experience.
 ```xml
 <input type="checkbox" t-att-checked="props.task.isCompleted"
     t-att-id="props.task.id"
-    t-on-click="dispatch('toggleTask', props.task.id)"/>
+    t-on-click="() => store.toggleTask(props.task)"/>
 <label t-att-for="props.task.id"><t t-esc="props.task.text"/></label>
 ```
 
@@ -770,10 +774,11 @@ For reference, here is the final code:
     <meta charset="UTF-8" />
     <title>OWL Todo App</title>
     <link rel="stylesheet" href="app.css" />
+  </head>
+  <body>
     <script src="owl.js"></script>
     <script src="app.js"></script>
-  </head>
-  <body></body>
+  </body>
 </html>
 ```
 

doc/readme.md

@@ -45,4 +45,5 @@ Utility/helpers:
 - [`loadFile`](reference/utils.md#loadfile): an helper to load a file from the server
 - [`markup`](reference/templates.md#outputting-data): utility function to define strings that represent html (should not be escaped)
 - [`status`](reference/component.md#status-helper): utility function to get the status of a component (new, mounted or destroyed)
+- [`validate`](reference/utils.md#validate): validates if an object satisfies a specified schema
 - [`whenReady`](reference/utils.md#whenready): utility function to execute code when DOM is ready

doc/reference/app.md

@@ -61,6 +61,8 @@ The `config` object is an object with some of the following keys:
   templates (see [translations](translations.md))
 - **`templates (string | xml document)`**: all the templates that will be used by
   the components created by the application.
+- **`warnIfNoStaticProps (boolean, default=false)`**: if true, Owl will log a warning
+  whenever it encounters a component that does not provide a [static props description](props.md#props-validation).
 
 ## `mount` helper
 
@@ -117,3 +119,5 @@ Dev mode activates some additional checks and developer amenities:
 - [Props validation](./props.md#props-validation) is performed
 - [t-foreach](./templates.md#loops) loops check for key unicity
 - Lifecycle hooks are wrapped to report their errors in a more developer-friendly way
+- onWillStart and onWillUpdateProps will emit a warning in the console when they
+  take longer than 3 seconds in an effort to ease debugging the presence of deadlocks

doc/reference/component.md

@@ -76,7 +76,8 @@ The `Component` class has a very small API.
 
   By default, the render initiated by this method will stop at each child
   component if their props are (shallow) equal. To force a render to update
-  all child components, one can use the optional `deep` argument.
+  all child components, one can use the optional `deep` argument. Note that the
+  value of the `deep` argument needs to be a boolean, not a truthy value.
 
 ## Static Properties
 

doc/reference/context.md

@@ -1,105 +0,0 @@
-# 🦉 Context 🦉
-
-## Content
-
-- [Overview](#overview)
-- [Example](#example)
-- [Reference](#reference)
-  - [`Context`](#context)
-  - [`useContext`](#usecontext)
-
-## Overview
-
-The `Context` object provides a way to share data between an arbitrary number
-of components. Usually, data is passed from a parent to its children component,
-but when we have to deal with some mostly global information, this can be
-annoying, since each component will need to pass the information to each children,
-even though some or most of them will not use the information.
-
-With a `Context` object, each component can subscribe (with the `useContext` hook)
-to its state, and will be updated whenever the context state is updated.
-
-## Example
-
-Assume that we have an application with various components which needs to render
-differently depending on the size of the device. Here is how we could proceed
-to make sure that the information is properly shared. First, let us create a
-context, and add it to the environment:
-
-```js
-const deviceContext = new Context({ isMobile: true });
-App.env.deviceContext = deviceContext;
-```
-
-If we want to make it completely responsive, we need to update its value whenever
-the size of the screen is updated:
-
-```js
-const isMobile = () => window.innerWidth <= 768;
-window.addEventListener(
-  "resize",
-  owl.utils.debounce(() => {
-    const state = deviceContext.state;
-    if (state.isMobile !== isMobile()) {
-      state.isMobile = !state.isMobile;
-    }
-  }, 15)
-);
-```
-
-Then, each component that want can subscribe and render differently depending on the
-fact that we are in a mobile or desktop mode.
-
-```js
-class SomeComponent extends Component {
-  static template = xml`
-    <div>
-      <t t-if=device.isMobile>
-          some simplified user interface
-      </t>
-      <t t-else="">
-          a more advanced user interface
-      </t>
-    </div>`;
-  device = useContext(this.env.deviceContext);
-}
-```
-
-## Reference
-
-### `Context`
-
-A `Context` object should be created with a state object:
-
-```js
-const someContext = new Context({ some: "key" });
-```
-
-Its state is now available in the `state` key:
-
-```js
-someContext.state.some = "other key";
-```
-
-This is the way some global code (such as the responsive code above) should
-read and update the context state. However, components should not ever read the
-context state directly from the context, they should instead use the `useContext`
-hook to properly register themselves to state changes.
-
-Note that the `Context` hook is different from the React version. For example,
-there is no concept of provider/consumer. So, the `Context` feature does not
-by itself allow the use of a different context state depending on the component
-place in the component tree. However, this functionality can be obtained, if
-necessary, with the use of sub environment.
-
-### `useContext`
-
-The `useContext` hook is the normal way for a component to register themselve
-to context state changes. The `useContext` method returns the context state:
-
-```js
-device = useContext(this.env.deviceContext);
-```
-
-It is a simple observed state (with an owl `Observer`), which contains the shared
-information.

doc/reference/hooks.md

@@ -234,7 +234,8 @@ are defined by a function instead of just the dependencies.
 
 The `useEffect` hook takes two function: the effect function and the dependency
 function. The effect function perform some task and return (optionally) a cleanup
-function. The dependency function returns a list of dependencies. If any of these
+function. The dependency function returns a list of dependencies, these dependencies
+are passed as parameters in the effect function . If any of these
 dependencies changes, then the current effect will be cleaned up and reexecuted.
 
 Here is an example without any dependencies:

doc/reference/precompiling_templates.md

@@ -0,0 +1,30 @@
+# 🦉 Precompiling templates 🦉
+
+Owl is designed to be used by the Odoo javascript framework. Since Odoo handles
+its assets in its own non standard way, it was decided/assumed that Owl would
+compile templates at runtime.
+
+However, in some cases, it is not optimal, or even worse, not possible to do that.
+For example, browser extensions do not allow javascript code to create a new
+function (using the `new Function(...)` syntax).
+
+Therefore, in these cases, it is required to compile templates ahead of time. It
+is possible to do that in Owl, but the tooling is still rough. For now, the
+process is the following:
+
+1. write your templates in xml files (with a `t-name` directive to declare the name
+   of the template)
+2. Compile them in a `templates.js` file
+3. get the `owl.iife.runtime.js` file (which is a owl build without the compiler)
+4. bundle `owl.iife.runtime.js` and `template.js` with your assets (owl needs to
+   be positioned before the templates)
+
+Here is a more detailed explanation on how to compile xml files into a js file:
+
+1. clone the owl repository locally
+2. `npm install` to install all the required tooling
+3. `npm run build:runtime` to build the `owl.iife.runtime.js` file
+4. `npm run build:compiler` to build the template compiler
+5. `npm run compile_templates -- path/to/your/templates` will scan your target
+   folder, find all xml files, get all templates, compile them, and generate a
+   `templates.js` file.

doc/reference/props.md

@@ -4,6 +4,7 @@
 
 - [Overview](#overview)
 - [Definition](#definition)
+- [Props comparison](#props-comparison)
 - [Binding function props](#binding-function-props)
 - [Dynamic Props](#dynamic-props)
 - [Default Props](#default-props)
@@ -56,6 +57,47 @@ the `props` object contains the following keys:
 - for `ComponentA`: `a` and `b`,
 - for `ComponentB`: `model`,
 
+## Props comparison
+
+Whenever Owl encounters a subcomponent in a template, it performs a shallow
+comparison of all props. If they are all referentially equal, then the subcomponent
+will not even be updated. Otherwise, if at least one props has changed, then
+Owl will update it.
+
+However, in some cases, we know that two values are different, but they have the
+same effect, and should not be considered different by Owl. For example, anonymous
+functions in a template are always different, but most of them should not be
+considered different:
+
+```xml
+<t t-foreach="todos" t-as="todo" t-key="todo.id">
+  <Todo todo="todo" onDelete="() => deleteTodo(todo.id)" />
+</t>
+```
+
+In that case, one can use the `.alike` suffix:
+
+```xml
+<t t-foreach="todos" t-as="todo" t-key="todo.id">
+  <Todo todo="todo" onDelete.alike="() => deleteTodo(todo.id)" />
+</t>
+```
+
+This tells Owl that this specific prop should always be considered equivalent
+(or, in other words, should be removed from the list of comparable props).
+
+Note that even if most anonymous functions should probably be considered `alike`,
+it is not necessarily true in all cases. It depends on what values are captured
+by the anonymous function. The following example shows a case where it is probably
+wrong to use `.alike`.
+
+```xml
+<t t-foreach="todos" t-as="todo" t-key="todo.id">
+  <!-- Probably wrong! todo.isCompleted may change -->
+  <Todo todo="todo" toggle.alike="() => toggleTodo(todo.isCompleted)" />
+</t>
+```
+
 ## Binding function props
 
 It is common to have the need to pass a callback as a prop. Since Owl components
@@ -95,6 +137,9 @@ class SomeComponent extends Component {
 }
 ```
 
+The `.bind` suffix also implies `.alike`, so these props will not cause additional
+renderings.
+
 ## Dynamic Props
 
 The `t-props` directive can be used to specify totally dynamic props:
@@ -159,6 +204,7 @@ For each key, a `prop` definition is either a boolean, a constructor, a list of
 - a boolean: indicate that the props exists, and is mandatory.
 - a constructor: this should describe the type, for example: `id: Number` describe
   the props `id` as a number
+- an object describing a value as type. This is done by using the `value` key. For example, `{value: false}` specifies that the corresponding value should be equal to false.
 - a list of constructors. In that case, this means that we allow more than one
   type. For example, `id: [Number, String]` means that `id` can be either a string
   or a number.
@@ -240,9 +286,12 @@ class ComponentB extends owl.Component {
     size: {
       validate:  e => ["small", "medium", "large"].includes(e)
     },
+    someId: [Number, {value: false}], // either a number or false
   };
 ```
 
+Note: the props validation code is done by using the [validate utility function](utils.md#validate).
+
 ## Good Practices
 
 A `props` object is a collection of values that come from the parent. As such,

doc/reference/reactivity.md

@@ -2,130 +2,394 @@
 
 ## Content
 
-- [Overview](#overview)
+- [Introduction](#introduction)
 - [`useState`](#usestate)
 - [`reactive`](#reactive)
-- [`markRaw`](#markraw)
-- [`toRaw`](#toraw)
+- [`Escape hatches`](#escape-hatches)
+- [`Advanced usage`](#advanced-usage)
 
-## Overview
+## Introduction
 
 Reactivity is a big topic in javascript frameworks. The goal is to provide a
-simple way to manipulate state, in such a way that the interface automatically
-update accordingly to state changes. Also, we obviously want this to happen in
-a performant way.
+simple way to manipulate state, in such a way that the interface updates automatically
+according to state changes, and to do so in a performant manner.
 
-To solve this issue, Owl provides two reactivity primitives:
-
-- `reactive`, which returns a proxy to its first argument, and tracks all read/update
-  operation going through it,
-- `useState`: a hook, that internally uses `reactive`, and is linked to its
-  owner component: any read operation will be tracked (key by key), and any
-  updates to these tracked values will cause the component to be rerendered.
-
-Most of the time, the `useState` hook is the best solution.
-
-Since version 2.0, Owl applies the fine grained reactivity at the component
-level: props are automatically turned into reactive object, so Owl can track
-which part of these props are consumed by each component, and is therefore able
-to only rerender the impacted components.
+To this end, Owl provides a proxy-based reactivity system, based on the `reactive` primitive.
+The `reactive` function takes an object as a first argument, and an optional callback as its second
+argument, it returns a proxy of the object. This proxy tracks what properties are read
+through the proxy, and calls the provided callback whenever one of these properties is changed
+through any reactive version of the same object. It does so in depth, by returning reactive versions
+of the subobjects when they are read.
 
 ## `useState`
 
-Let us start by an example of how `useState` could be used:
+While the `reactive` primitive is very powerful, its usage in components follow a very standard pattern:
+components want to be rerendered when part of the state which they depend on for rendering changes. To
+this end, owl provides a standard hook: `useState`. To put it simply, this hook simply calls reactive
+with the provided object, and the current component's render function as its callback. This will cause
+it to rerender whenever any part of the state object that has been read by this component is modified.
+
+Here is a simple example of how `useState` can be used:
 
 ```js
 class Counter extends Component {
   static template = xml`
-    <div t-on-click="increment">
+    <div t-on-click="() => this.state.value++">
       <t t-esc="state.value"/>
     </div>`;
 
   setup() {
     this.state = useState({ value: 0 });
   }
+}
+```
 
-  increment() {
-    this.state.value++;
+This component reads `state.value` when it renders, subscribing it to changes to that key. Whenever
+the value changes, Owl will update the component. Note that there is nothing special about the
+`state` property, you can name your state variables whatever you want, and you can have multiple of
+them on the same component if it makes sense to do so. This also allows `useState` to be used in custom
+hooks that may require state that is specific to that hook.
+
+### Reactive props
+
+Since version 2.0, Owl renders are no longer "deep" by default: a component is only rerendered by its
+parent if its props have changed (using a simple equality test). What if the contents of a props have
+changed in a deeper property? If that prop is reactive, owl will rerender the child components that
+need to be updated automatically, and only those components, it does so by reobserving reactive
+objects passed as props to components. Consider the following example:
+
+```js
+class Counter extends Component {
+  static template = xml`
+    <div t-on-click="() => props.state.value++">
+      <t t-esc="props.state.value"/>
+    </div>`;
+}
+
+class Parent extends Component {
+  static template = xml`
+    <Counter state="this.state"/>
+    <button t-on-click="() => this.state.value = 0">Reset counter</button>
+    <button t-on-click="() => this.state.test++" t-esc="this.state.test"/>`;
+
+  setup() {
+    this.state = useState({ value: 0, test: 1 });
   }
 }
 ```
 
-If one were to use a simple state object, Owl would not be aware that the value
-was changed and that the component should be rerendered. With the `useState`
-hook, `this.state` is now a reactive object, so this component works as expected.
+When clicking on the counter button, only the Counter rerenders, because the Parent has never read
+the "value" key in the state. When clicking on the "Reset Counter" button, the same thing happens:
+only the Counter component rerenders. What matters is not _where_ the state is updated, but which
+parts of the state are updated, and which components depend on them. This is achieved by Owl by
+automatically calling `useState` on reactive objects passed as props to a child component.
+
+When clicking on the last button, the parent is rerendered, but the child does not care about the
+`test` key: it has not read it. The props that we give it (`this.state`) have also not changed,
+as such, the parent updates but the child doesn't.
+
+For most day-to-day operations, `useState` should cover all of your needs. If
+you are curious about more advanced use cases and technical details, read on.
+
+### Debugging subscriptions
+
+Owl provides a way to show which reactive objects and keys a component is subscribed to: you can
+look at `component.__owl__.subscriptions`. Note that this is on the internal `__owl__` field, and
+should not be used in any type of production code as the name of this property or any of its properties
+or methods are subject to change at any point, even in stable versions of Owl, and may become available
+only in debug mode in the future.
 
 ## `reactive`
 
 The `reactive` function is the basic reactivity primitive. It takes an object
 or an array as first argument, and optionally, a function as the second argument.
-The function will be called whenever any tracked value is updated.
+The function is called whenever any tracked value is updated.
 
 ```js
 const obj = reactive({ a: 1 }, () => console.log("changed"));
 
-obj.a = 2; // does not log anything: the 'a' key was not read
-console.log(obj.a); // log 2, and reads the 'a' key => it is now tracked
-obj.a = 3; // log 'changed' because we updated a tracked value
+obj.a = 2; // does not log anything: the 'a' key has not been read yet
+console.log(obj.a); // logs 2 and reads the 'a' key => it is now tracked
+obj.a = 3; // logs 'changed' because we updated a tracked value
 ```
 
 An important property of reactive objects is that they can be reobserved: this
-will create an independant proxy that tracks another set of keys:
+will create an independent proxy that tracks another set of keys:
 
 ```js
 const obj1 = reactive({ a: 1, b: 2 }, () => console.log("observer 1"));
 const obj2 = reactive(obj1, () => console.log("observer 2"));
 
-console.log(obj1.a); // log 1, and reads the 'a' key => it is now tracked by observer 1
-console.log(obj1.b); // log 2, and 'b' is now tracked by observer 1
-console.log(obj2.b); // log 2, and 'b' is now tracked by observer 1
-obj2.a = 3; // log 'observer1', because observer2 does not track a
-obj2.b = 3; // log 'observer1' and 'observer2'
+console.log(obj1.a); // logs 1, and reads the 'a' key => it is now tracked by observer 1
+console.log(obj2.b); // logs 2, and 'b' is now tracked by observer 2
+obj2.a = 3; // only logs 'observer1', because observer2 does not track a
+obj2.b = 3; // only logs 'observer2', because observer1 does not track b
+console.log(obj2.a, obj1.b); // logs 3 and 3, while the object is observed independently, it is still a single object
 ```
 
-Obviously, one can use `reactive` on the result of a `useState` if wanted, this
-is the proper way to watch for some state changes.
+Because `useState` returns a normal reactive object, it is possible to call `reactive` on the result
+of a `useState` to observe changes to that object while outside the context of a component, or to
+call `useState` on reactive objects created outside of components. In those cases, one needs to be
+careful with regards to the lifetime of those reactive objects, as holding references to these
+objects may prevent garbage collection of the component and its data even if Owl has destroyed it.
 
-## `markRaw`
+### Subscriptions are ephemereal
 
-Marks an object so that it is ignored by the reactivity system. This function returns its argument.
+Subscription to state changes are ephemereal, whenever an observer is notified that a state object
+has changed, all of its subscriptions are cleared, meaning that if it still cares about it, it
+should read the properties it cares about again. For example:
 
 ```js
-const someObject = markRaw(...);
+const obj = reactive({ a: 1 }, () => console.log("observer called"));
+
+console.log(obj.a); // logs 1, and reads the 'a' key => it is now tracked by the observer
+obj.a = 3; // logs 'observer1' and clears the subscriptions of the observer
+obj.a = 4; // doesn't log anything, the key is no longer observed
+```
+
+This may seem counter-intuitive, but it makes perfect sense in the context of components:
+
+```js
+class DoubleCounter extends Component {
+  static template = xml`
+    <t t-esc="state.selected + ': ' + state[state.selected].value"/>
+    <button t-on-click="() => this.state.count1++">increment count 1</button>
+    <button t-on-click="() => this.state.count2++">increment count 2</button>
+    <button t-on-click="changeCounter">Switch counter</button>
+  `;
+
+  setup() {
+    this.state = useState({ selected: "count1", count1: 0, count2: 0 });
+  }
+
+  changeCounter() {
+    this.state.selected = this.state.selected === "count1" ? "count2" : "count1";
+  }
+}
+```
+
+In this component, if we increment the value of the second counter, the component will not rerender,
+which makes sense as rerendering will have no effect, as the second counter is not displayed. If we
+toggle the component to display the second counter, we now no longer want the component to rerender
+when the value of the first counter changes, and this is what happens: a component only rerenders
+when there are changes to pieces of state that have been read during or after the previous render.
+If a piece of state has not been read in the last render, we know that its value won't influence the
+rendered output, and so we can ignore it.
+
+### reactive `Map` and `Set`
+
+The reactivity system has special support built-in for the standard container types `Map` and `Set`.
+They behave like one would expect: reading a key subscribes the observer to that key, adding or
+removing an item to them notifies observers that have used any of the iterators on that reactive
+object, such as `.entries()` or `.keys()`, likewise with clearing them.
+
+## Escape hatches
+
+Sometimes, it is desirable to bypass the reactivity system. Creating proxies when interacting with
+reactive objects is expensive, and while on the whole, the performance benefit that we get by
+rerendering only the parts of the interface that need it outweighs that cost, in some cases, we want
+to be able to opt out of creating them in the first place. This is the purpose of `markRaw`:
+
+### `markRaw`
+
+Marks an object so that it is ignored by the reactivity system, meaning that if this object is ever
+part of a of a reactive object, it will be returned as is, and no keys in that object will be
+observed.
+
+```js
+const someObject = markRaw({ b: 1 });
 const state = useState({
   a: 1,
-  obj: someObject
+  obj: someObject,
 });
-// here, state.obj === someObject
+console.log(state.obj.b); // attempt to subscribe to the "b" key in someObject
+state.obj.b = 2; // No rerender will occur here
+console.log(someObject === state.obj); // true
 ```
 
-This is useful in some rare cases. For example, some complex and large object such
-that going through the reactivity system may cause a non trivial performance slowdown.
+This is useful in some rare cases. One such example would be if you want to use an array of objects
+that is potentially large to render a list, but those objects are known to be immutable:
+
+```js
+this.items = useState([
+  { label: "some text", value: 42 },
+  // ... 1000 total objects
+]);
+```
+
+in the template:
+
+```xml
+<t t-foreach="items" t-as="item" t-key="item.label" t-esc="item.label + item.value"/>
+```
+
+Here, on every render, we go and read one thousand keys from a reactive object, which causes
+one thousand reactive objects to be created. If we know that the content of these objects
+cannot change, this is wasted work. If instead all of these objects are marked as raw, we avoid
+all of this work while keeping the ability to lean on the reactivity to track the presence and
+identity of these objects:
+
+```js
+this.items = useState([
+  markRaw({ label: "some text", value: 42 }),
+  // ... 1000 total objects
+]);
+```
 
 However, use this function with caution: this is an escape hatch from the reactivity
-system, and as such, using it may cause subtle and unintended issues!
-
-## `toRaw`
-
-Given a reactive object, this function returns the underlying, non-reactive,
-corresponding object.
+system, and as such, using it may cause subtle and unintended issues! For example:
 
 ```js
-// in setup
-const state = useState({ value: 1 });
+// This will cause a rerender
+this.items.push(markRaw({ label: "another label", value: 1337 }));
 
-// later:
-const rawState = toRaw(this.state);
-rawState.value = 3; // will NOT be picked up by the reactivity system!!!
+// THIS WILL NOT CAUSE A RENDER!
+this.items[17].value = 3;
+// The UI is now desynced from component's state until the next render caused by something else
 ```
 
-Here again, this is useful in some situations where we want to explicitely bypass
-Owl, but using this function means that the responsability of coordinating
-state update is given to the user code, instead of Owl. Subtle bugs may arise!
+In short: only use `markRaw` if your application is slowing down noticeably and profiling reveals
+that a lot of time is spent creating useless reactive objects.
 
-Also, normal (non-reactive objects) will be directly returned by `toRaw`:
+### `toRaw`
+
+While `markRaw` marks an object so that it is never made reactive, `toRaw` takes an object and
+returns the underlying non-reactive object. It can be useful in some niche cases. In particular,
+because the reactivity system returns a proxy, the returned object does not compare equal to the
+original object:
 
 ```js
-const obj = { a: 1 };
-console.log(toRaw(obj) === obj); // true
+const obj = {};
+const reactiveObj = reactive(obj);
+console.log(obj === reactiveObj); // false
+console.log(obj === toRaw(reactiveObj)); // true
 ```
+
+It can also be useful during debugging, as unfolding proxies recursively in debuggers can be confusing.
+
+## Advanced usage
+
+The following is a collection of small snippets that leverage the reactivity system in
+"non-standard" ways to help you understand its power and where using it might make your code simpler.
+
+### Notification manager
+
+Showing notifications is a pretty common need in web applications, you may want to show a
+notification from any other component within the application, and the notifications should stack on
+top of one another regardless of which component spawned them, here is how we can leverage the
+reactivity to accomplish this:
+
+```js
+let notificationId = 1;
+const notifications = reactive({});
+class NotificationContainer extends Component {
+  static template = xml`
+    <t t-foreach="notifications" t-as="notification" t-key="notification_key" t-esc="notification"/>
+  `;
+  setup() {
+    this.notifications = useState(notifications);
+  }
+}
+
+export function addNotification(label) {
+  const id = notificationId++;
+  notifications[id] = label;
+  return () => {
+    delete notifications[id];
+  };
+}
+```
+
+Here, the `notifications` variable is a reactive object. Notice how we didn't give `reactive` a
+callback: this is because in this case, all we care about is that adding or removing notifications
+in the `addNotification` function goes through the reactivity system. The `NotificationContainer`
+component reobserves this object with `useState`, and is updated whenever notifications are
+added or removed.
+
+### Store
+
+Centralizing application state is a pretty common want/need in web applications. Because of the way
+the reactivity system works, you can treat any reactive object as a store, and if you call `useState`
+on it, components automatically observe only the part of the store that they're interested in:
+
+```js
+export const store = reactive({
+  list: [],
+  add(item) {
+    this.list.push(item);
+  },
+});
+
+export function useStore() {
+  return useState(store);
+}
+```
+
+In any component:
+
+```js
+import { useStore } from "./store";
+
+class List extends Component {
+  static template = xml`
+    <t t-foreach="store.list" t-as="item" t-key="item" t-esc="item"/>
+  `;
+  setup() {
+    this.store = useStore();
+  }
+}
+```
+
+Anywhere in the application:
+
+```js
+import { store } from "./store";
+// Will cause any instance of the List component in the app to update
+store.add("New list item!");
+```
+
+Notice how we can make objects with methods into reactive objects, and when these methods are used
+to mutate the store contents, it works as expected. And while stores are generally one-off objects,
+it is entirely possible to make class instances reactive:
+
+```js
+class Store {
+  list = [];
+  add(item) {
+    this.list.push(item);
+  }
+}
+// Essentially equivalent to the previous code
+export const store = reactive(new Store());
+```
+
+Which can be useful to unit test the class separately.
+
+### Local storage synchronization
+
+Sometimes, you want to persist some state accross reloads, you can do this by storing it in the
+`localStorage`, but what if you want to update the `localStorage` item every time the state changes,
+so that you don't have to manually synchronize the states? Well, you can use the reactivity system
+to write a custom hook that will do that for you:
+
+```js
+function useStoredState(key, initialState) {
+  const state = JSON.parse(localStorage.getItem(key)) || initialState;
+  const store = (obj) => localStorage.setItem(key, JSON.stringify(obj));
+  const reactiveState = reactive(state, () => store(reactiveState));
+  store(reactiveState);
+  return useState(state);
+}
+
+class MyComponent extends Component {
+  setup() {
+    this.state = useStoredState("MyComponent.state", { value: 1 });
+  }
+}
+```
+
+One important thing to notice is that both times we call `store`, we call it with `reactiveState`,
+not `state`: we need `store` to read the keys through a reactive object for it to correctly
+subscribe to state changes. Notice also that we call `store` the first time by hand, as otherwise it
+will not be subscribed to anything, and no amount of change in the object will cause the reactive
+callback to be invoked.

doc/reference/slots.md

@@ -239,6 +239,12 @@ And the child component that includes the slot can provide values like this:
 <t t-slot="foo" bool="other_var" num="5">
 ```
 
+or this:
+
+```xml
+<t t-slot="foo" t-props="someObject">
+```
+
 In the case of the default slot, you may declare the slot scope directly on the
 component itself:
 

doc/reference/templates.md

@@ -115,7 +115,7 @@ It is useful to explain the various rules that apply on these expressions:
    <div><p t-if="console.log(1)">NOT valid</p></div>
    ```
 
-2. it can use anything in the rendering context (typically, the component):
+2. it can use anything in the rendering context (which typically contains the properties of the component):
 
    ```xml
    <p t-if="user.birthday === today()">Happy bithday!</p>
@@ -290,10 +290,11 @@ If an expression evaluates to a falsy value, it will not be set at all:
 
 It is sometimes convenient to format an attribute with string interpolation. In
 that case, the `t-attf-` directive can be used. It is useful when we need to mix
-literal and dynamic elements, such as css classes.
+literal and dynamic elements, such as css classes. The dynamic elements can be
+specified with either `{{...}}` or `#{...}`:
 
 ```xml
-<div t-attf-foo="a {{value1}} is {{value2}} of {{value3}} ]"/>
+<div t-attf-foo="a {{value1}} is #{value2} of {{value3}} ]"/>
 <!-- result if values are set to 1,2 and 3: <div foo="a 0 is 1 of 2 ]"></div> -->
 ```
 
@@ -476,7 +477,7 @@ not work with other iterables, such as `Set`. However, it is only a matter of
 using the `...` javascript operator. For example:
 
 ```xml
-<t t-foreach="...items" t-as="item">...</t>
+<t t-foreach="[...items]" t-as="item">...</t>
 ```
 
 The `...` operator will convert the `Set` (or any other iterables) into a list,
@@ -539,6 +540,14 @@ This can be used to define variables scoped to a sub template:
 <!-- "var" does not exist here -->
 ```
 
+Note: by default, the rendering context for a sub template is simply the current
+rendering context. However, it may be useful to be able to specify a specific
+object as context. This can be done by using the `t-call-context` directive:
+
+```xml
+<t t-call="other-template" t-call-context="obj"/>
+```
+
 ### Dynamic sub templates
 
 The `t-call` directive can also be used to dynamically call a sub template,

doc/reference/utils.md

@@ -8,6 +8,7 @@ functions are all available in the `owl.utils` namespace.
 - [`whenReady`](#whenready): executing code when DOM is ready
 - [`loadFile`](#loadfile): loading a file (useful for templates)
 - [`EventBus`](#eventbus): a simple EventBus
+- [`validate`](#validate): a validation function
 
 ## `whenReady`
 
@@ -56,3 +57,24 @@ bus.addEventListener("event", () => console.log("something happened"));
 
 bus.trigger("event"); // 'something happened' is logged
 ```
+
+## `validate`
+
+The `validate` function is a function that validates if a given object satisfies a
+specified schema. It is actually used by Owl itself to perform
+[props validation](props.md#props-validation). For example:
+
+```js
+validate(
+  { a: "hey" },
+  {
+    id: Number,
+    url: [Boolean, { type: Array, element: Number }],
+  }
+);
+
+// throws an error with the following information:
+//    - unknown key 'a',
+//    - 'id' is missing (should be a number),
+//    - 'url' is missing (should be a boolean or list of numbers),
+```

doc/tools/devtools.md

@@ -0,0 +1,54 @@
+# Owl Devtools Browser extension
+
+The owl devtools browser extension is an extension available on chrome or firefox which adds an owl tab
+to the browser devtools in order to inspect all owl apps that are present on any web page, their components
+and allows to interract with their data to a certain extend. There is also a profiler available to visualize
+the components' lifecycle and be able to trace their origin.
+
+## Install the extension
+
+In the owl root folder:
+
+```bash
+npm install
+```
+
+For chrome:
+
+```bash
+npm run build:devtools-chrome
+```
+
+For firefox:
+
+```bash
+npm run build:devtools-firefox
+```
+
+You can also run:
+
+```bash
+npm run dev:devtools-chrome
+```
+
+or
+
+```bash
+npm run dev:devtools-firefox
+```
+
+to avoid recompiling owl and gain time if it has already been done.
+
+To run the extension:
+
+In google chrome: go to your chrome extensions admin panel, activate developer mode and click on `Load unpacked`.
+Select the output folder (dist/devtools) and that's it, your extension is active!
+There is a convenient refresh button on the extension card (still on the same admin page) to update your code.
+Do note that if you got some problems, you may need to completly remove and reload the extension to completly refresh the extension.
+
+In firefox: go to the address about:debugging#/runtime/this-firefox and click on `Load temporary Add-on...`.
+Select any file of the output folder (dist/devtools) and that's it, your extension is active!
+Here, you can use the reload button to refresh the extension.
+
+Note that you may have to open another window or reload your tab to see the extension working.
+Also note that the extension will only be active on pages that have a sufficient version of owl.

package.json

@@ -1,11 +1,10 @@
 {
   "name": "@odoo/owl",
-  "version": "2.0.0-beta.3",
+  "version": "2.1.0",
   "description": "Odoo Web Library (OWL)",
   "main": "dist/owl.cjs.js",
-  "browser": "dist/owl.iife.js",
   "module": "dist/owl.es.js",
-  "types": "dist/types/index.d.ts",
+  "types": "dist/types/owl.d.ts",
   "files": [
     "dist"
   ],
@@ -14,7 +13,14 @@
   },
   "scripts": {
     "build:bundle": "rollup -c --failAfterWarnings",
+    "build:runtime": "rollup -c --failAfterWarnings runtime",
+    "build:compiler": "rollup -c --failAfterWarnings compiler",
     "build": "npm run build:bundle",
+    "build:devtools": "rollup -c ./tools/devtools/rollup.config.js",
+    "dev:devtools-chrome": "npm run build:devtools -- --config-browser=chrome",
+    "dev:devtools-firefox": "npm run build:devtools -- --config-browser=firefox",
+    "build:devtools-chrome": "NODE_ENV=production npm run dev:devtools-chrome",
+    "build:devtools-firefox": "NODE_ENV=production npm run dev:devtools-firefox",
     "test": "jest",
     "test:debug": "node --inspect-brk node_modules/.bin/jest --runInBand --watch --testTimeout=5000000",
     "test:watch": "jest --watch",
@@ -22,10 +28,12 @@
     "playground": "npm run build && npm run playground:serve",
     "preplayground:watch": "npm run build",
     "playground:watch": "npm-run-all  --parallel playground:serve \"build:* -- --watch\"",
-    "prettier": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md} --write",
-    "check-formatting": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md} --check",
+    "prettier": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md,tools/devtools/**/*.js} --write",
+    "check-formatting": "prettier {src/*.ts,src/**/*.ts,tests/*.ts,tests/**/*.ts,doc/*.md,doc/**/*.md,tools/devtools/**/*.js} --check",
+    "lint": "eslint src/**/*.ts tests/**/*.ts",
     "publish": "npm run build && npm publish",
-    "release": "node tools/release.js"
+    "release": "node tools/release.js",
+    "compile_templates": "node tools/compile_xml.js"
   },
   "repository": {
     "type": "git",
@@ -40,25 +48,29 @@
   "devDependencies": {
     "@types/jest": "^27.0.1",
     "@types/node": "^14.11.8",
+    "@typescript-eslint/eslint-plugin": "5.48.1",
+    "@typescript-eslint/parser": "5.48.1",
     "chalk": "^3.0.0",
-    "cpx": "^1.5.0",
     "current-git-branch": "^1.1.0",
-    "git-rev-sync": "^1.12.0",
+    "eslint": "8.31.0",
+    "git-rev-sync": "^3.0.2",
     "github-api": "^3.3.0",
     "jest": "^27.1.0",
     "jest-diff": "^27.3.1",
     "jest-environment-jsdom": "^27.1.0",
-    "live-server": "^1.2.1",
     "npm-run-all": "^4.1.5",
     "prettier": "2.4.1",
     "rollup": "^2.56.3",
+    "rollup-plugin-copy": "^3.3.0",
+    "rollup-plugin-delete": "^2.0.0",
+    "rollup-plugin-dts": "^4.2.2",
+    "rollup-plugin-execute": "^1.1.1",
+    "rollup-plugin-string": "^3.0.0",
     "rollup-plugin-terser": "^7.0.2",
     "rollup-plugin-typescript2": "^0.31.1",
-    "sass": "^1.16.1",
     "source-map-support": "^0.5.10",
     "ts-jest": "^27.0.5",
-    "typescript": "4.5.2",
-    "uglify-es": "^3.3.9"
+    "typescript": "4.5.2"
   },
   "jest": {
     "testEnvironment": "jsdom",

roadmap.md

@@ -1,28 +1,9 @@
 # 🦉 OWL Roadmap 🦉
 
-- Current version: 1.4.10
+- Current version: 2.X
 - Status: stable
 
-This roadmap is only an attempt at predicting Owl's future.  Everything may
-change!
-
-
-### 1.x
-
-- add chrome and firefox devtools,
-- fix every bugs,
-- improve documentation,
-- small backward compatible improvements.
-
-### 2.x (2020? 2021? 2022?)
-
-- stop support for `t-set` directive to define the content of a slot
-
-Maybe:
-
-- reimplement vdom to use *block* system, like Vue 3, which should make Owl
-  much faster
-- refactor `QWeb` to use an intermediate representation (some kind of AST) to
-  allow additional optimisations.
-
+Owl is currently stable. No (large) improvements is expected in the near future.
 
+Note that we intend to keep maintaining owl, and as such, improvements and/or
+breaking changes may require a version bump in the future.

rollup.config.js

@@ -2,28 +2,57 @@ import pkg from "./package.json";
 import git from "git-rev-sync";
 import typescript from 'rollup-plugin-typescript2';
 import { terser } from "rollup-plugin-terser";
+import dts from "rollup-plugin-dts";
 
-const name = "owl";
-const extend = true;
+let input, output;
+
+const IIFE_FILENAME = "dist/owl.iife.js";
+const CJS_FILENAME = "dist/owl.cjs.js";
+const ES_FILENAME = "dist/owl.es.js";
+
+if (pkg.module !== ES_FILENAME || pkg.main !== CJS_FILENAME) {
+  throw new Error("package.json has been modified. Build script should be updated accordingly");
+}  
 
-/**
- * Meta data to be added on the __info__ object.
- * Used to let external tools know the current owl version.
- */
 const outro = `
-__info__.version = '${pkg.version}';
 __info__.date = '${new Date().toISOString()}';
 __info__.hash = '${git.short()}';
 __info__.url = 'https://github.com/odoo/owl';
 `;
 
+switch (process.argv[4]) {
+  case "compiler": 
+    input = "src/compiler/index.ts",
+    output = [
+      getConfigForFormat('cjs', 'dist/compiler.js', ''),
+    ]
+    break;
+  case "runtime":
+    input = "src/runtime/index.ts";
+    output = [
+      getConfigForFormat('esm', addSuffix(ES_FILENAME,  'runtime'), outro),
+      getConfigForFormat('cjs', addSuffix(CJS_FILENAME,  'runtime'), outro),
+      getConfigForFormat('iife', addSuffix(IIFE_FILENAME,  'runtime'), outro),
+      getConfigForFormat('iife', addSuffix(IIFE_FILENAME,  'runtime'), outro, true),
+    ]
+    break;
+  default:
+    input = "src/index.ts",
+    output = [
+      getConfigForFormat('esm', ES_FILENAME, outro),
+      getConfigForFormat('cjs', CJS_FILENAME, outro),
+      getConfigForFormat('iife', IIFE_FILENAME, outro),
+      getConfigForFormat('iife', IIFE_FILENAME, outro, true),
+    ]
+  }
+
 /**
  * Generate from a string depicting a path a new path for the minified version.
  * @param {string} pkgFileName file name
  */
-function generateMinifiedNameFromPkgName(pkgFileName) {
+function addSuffix(pkgFileName, suffix) {
   const parts = pkgFileName.split('.');
-  parts.splice(parts.length - 1, 0, "min");
+  parts.splice(parts.length - 1, 0, suffix);
   return parts.join('.');
 }
 
@@ -33,12 +62,12 @@ function generateMinifiedNameFromPkgName(pkgFileName) {
  * @param {string} generatedFileName generated file name
  * @param {boolean} minified should it be minified
  */
-function getConfigForFormat(format, generatedFileName, minified = false) {
+function getConfigForFormat(format, generatedFileName, outro, minified = false) {
   return {
-    file: minified ? generateMinifiedNameFromPkgName(generatedFileName) : generatedFileName,
+    file: minified ? addSuffix(generatedFileName, "min") : generatedFileName,
     format: format,
-    name: name,
-    extend: extend,
+    name: "owl",
+    extend: true,
     outro: outro,
     freeze: false,
     plugins: minified ? [terser()] : [],
@@ -46,26 +75,19 @@ function getConfigForFormat(format, generatedFileName, minified = false) {
   };
 }
 
-export default {
-  input: "src/index.ts",
-  output: [
-
-    /**
-     * Read about module formats:
-     *  https://auth0.com/blog/javascript-module-systems-showdown/
-     *  https://medium.com/@kelin2025/so-you-wanna-use-es6-modules-714f48b3a953
-     */
-
-    getConfigForFormat('esm', pkg.module),
-    getConfigForFormat('esm', pkg.module, true),
-    getConfigForFormat('cjs', pkg.main),
-    getConfigForFormat('cjs', pkg.main, true),
-    getConfigForFormat('iife', pkg.browser),
-    getConfigForFormat('iife', pkg.browser, true),
-  ],
-  plugins: [
-    typescript({
-      useTsconfigDeclarationDir: true
-    }),
-  ]
-};
+export default [
+  {
+    input,
+    output,
+    plugins: [
+      typescript({
+        useTsconfigDeclarationDir: true
+      }),
+    ]
+  },
+  {
+    input: "dist/types/index.d.ts",
+    output: [{ file: "dist/types/owl.d.ts", format: "es" }],
+    plugins: [dts()],
+  },
+];

src/app/app.ts

@@ -1,119 +0,0 @@
-import { Component, ComponentConstructor } from "../component/component";
-import { ComponentNode } from "../component/component_node";
-import { MountOptions } from "../component/fibers";
-import { Scheduler } from "../component/scheduler";
-import { TemplateSet, TemplateSetConfig } from "./template_set";
-import { nodeErrorHandlers } from "../component/error_handling";
-import { validateTarget } from "../utils";
-
-// reimplement dev mode stuff see last change in 0f7a8289a6fb8387c3c1af41c6664b2a8448758f
-
-export interface Env {
-  [key: string]: any;
-}
-
-export interface AppConfig<P, E> extends TemplateSetConfig {
-  props?: P;
-  env?: E;
-  test?: boolean;
-}
-
-let hasBeenLogged = false;
-
-export const DEV_MSG = () => {
-  const hash = (window as any).owl ? (window as any).owl.__info__.hash : "master";
-
-  return `Owl is running in 'dev' mode.
-
-This is not suitable for production use.
-See https://github.com/odoo/owl/blob/${hash}/doc/reference/app.md#configuration for more information.`;
-};
-
-export class App<
-  T extends abstract new (...args: any) => any = any,
-  P extends object = any,
-  E = any
-> extends TemplateSet {
-  static validateTarget = validateTarget;
-
-  Root: ComponentConstructor<P, E>;
-  props: P;
-  env: E;
-  scheduler = new Scheduler();
-  root: ComponentNode<P, E> | null = null;
-
-  constructor(Root: ComponentConstructor<P, E>, config: AppConfig<P, E> = {}) {
-    super(config);
-    this.Root = Root;
-    if (config.test) {
-      this.dev = true;
-    }
-    if (this.dev && !config.test && !hasBeenLogged) {
-      console.info(DEV_MSG());
-      hasBeenLogged = true;
-    }
-    const env = config.env || {};
-    const descrs = Object.getOwnPropertyDescriptors(env);
-    this.env = Object.freeze(Object.create(Object.getPrototypeOf(env), descrs));
-    this.props = config.props || ({} as P);
-  }
-
-  mount(target: HTMLElement, options?: MountOptions): Promise<Component<P, E> & InstanceType<T>> {
-    App.validateTarget(target);
-    const node = this.makeNode(this.Root, this.props);
-    const prom = this.mountNode(node, target, options);
-    this.root = node;
-    return prom;
-  }
-
-  makeNode(Component: ComponentConstructor, props: any): ComponentNode {
-    return new ComponentNode(Component, props, this);
-  }
-
-  mountNode(node: ComponentNode, target: HTMLElement, options?: MountOptions) {
-    const promise: any = new Promise((resolve, reject) => {
-      let isResolved = false;
-      // manually set a onMounted callback.
-      // that way, we are independant from the current node.
-      node.mounted.push(() => {
-        resolve(node.component);
-        isResolved = true;
-      });
-
-      // Manually add the last resort error handler on the node
-      let handlers = nodeErrorHandlers.get(node);
-      if (!handlers) {
-        handlers = [];
-        nodeErrorHandlers.set(node, handlers);
-      }
-      handlers.unshift((e) => {
-        if (isResolved) {
-          console.error(e);
-        } else {
-          reject(e);
-        }
-        throw e;
-      });
-    });
-    node.mountComponent(target, options);
-    return promise;
-  }
-
-  destroy() {
-    if (this.root) {
-      this.root.destroy();
-    }
-  }
-}
-
-export async function mount<
-  T extends abstract new (...args: any) => any = any,
-  P extends object = any,
-  E = any
->(
-  C: T & ComponentConstructor<P, E>,
-  target: HTMLElement,
-  config: AppConfig<P, E> & MountOptions = {}
-): Promise<Component<P, E> & InstanceType<T>> {
-  return new App(C, config).mount(target, config);
-}

src/app/template_helpers.ts

@@ -1,203 +0,0 @@
-import { BDom, multi, text, toggler, createCatcher } from "../blockdom";
-import { validateProps } from "../component/props_validation";
-import { Markup } from "../utils";
-import { html } from "../blockdom/index";
-import { TARGET } from "../reactivity";
-
-/**
- * This file contains utility functions that will be injected in each template,
- * to perform various useful tasks in the compiled code.
- */
-
-function withDefault(value: any, defaultValue: any): any {
-  return value === undefined || value === null || value === false ? defaultValue : value;
-}
-
-function callSlot(
-  ctx: any,
-  parent: any,
-  key: string,
-  name: string,
-  dynamic: boolean,
-  extra: any,
-  defaultContent?: (ctx: any, node: any, key: string) => BDom
-): BDom {
-  key = key + "__slot_" + name;
-  const slots = ctx.props[TARGET].slots || {};
-  const { __render, __ctx, __scope } = slots[name] || {};
-  const slotScope = Object.create(__ctx || {});
-  if (__scope) {
-    slotScope[__scope] = extra;
-  }
-  const slotBDom = __render ? __render.call(__ctx.__owl__.component, slotScope, parent, key) : null;
-  if (defaultContent) {
-    let child1: BDom | undefined = undefined;
-    let child2: BDom | undefined = undefined;
-    if (slotBDom) {
-      child1 = dynamic ? toggler(name, slotBDom) : slotBDom;
-    } else {
-      child2 = defaultContent.call(ctx.__owl__.component, ctx, parent, key);
-    }
-    return multi([child1, child2]);
-  }
-  return slotBDom || text("");
-}
-
-function capture(ctx: any): any {
-  const component = ctx.__owl__.component;
-  const result = Object.create(component);
-  for (let k in ctx) {
-    result[k] = ctx[k];
-  }
-  return result;
-}
-
-function withKey(elem: any, k: string) {
-  elem.key = k;
-  return elem;
-}
-
-function prepareList(collection: any): [any[], any[], number, any[]] {
-  let keys: any[];
-  let values: any[];
-
-  if (Array.isArray(collection)) {
-    keys = collection;
-    values = collection;
-  } else if (collection) {
-    values = Object.keys(collection);
-    keys = Object.values(collection);
-  } else {
-    throw new Error("Invalid loop expression");
-  }
-  const n = values.length;
-  return [keys, values, n, new Array(n)];
-}
-
-const isBoundary = Symbol("isBoundary");
-
-function setContextValue(ctx: { [key: string]: any }, key: string, value: any): void {
-  const ctx0 = ctx;
-  while (!ctx.hasOwnProperty(key) && !ctx.hasOwnProperty(isBoundary)) {
-    const newCtx = ctx.__proto__;
-    if (!newCtx) {
-      ctx = ctx0;
-      break;
-    }
-    ctx = newCtx;
-  }
-  ctx[key] = value;
-}
-
-function toNumber(val: string): number | string {
-  const n = parseFloat(val);
-  return isNaN(n) ? val : n;
-}
-
-function shallowEqual(l1: any[], l2: any[]): boolean {
-  for (let i = 0, l = l1.length; i < l; i++) {
-    if (l1[i] !== l2[i]) {
-      return false;
-    }
-  }
-  return true;
-}
-
-class LazyValue {
-  fn: any;
-  ctx: any;
-  node: any;
-  constructor(fn: any, ctx: any, node: any) {
-    this.fn = fn;
-    this.ctx = capture(ctx);
-    this.node = node;
-  }
-
-  evaluate(): any {
-    return this.fn(this.ctx, this.node);
-  }
-
-  toString() {
-    return this.evaluate().toString();
-  }
-}
-
-/*
- * Safely outputs `value` as a block depending on the nature of `value`
- */
-export function safeOutput(value: any): ReturnType<typeof toggler> {
-  if (!value) {
-    return value;
-  }
-  let safeKey;
-  let block;
-  if (value instanceof Markup) {
-    safeKey = `string_safe`;
-    block = html(value as string);
-  } else if (value instanceof LazyValue) {
-    safeKey = `lazy_value`;
-    block = value.evaluate();
-  } else if (value instanceof String || typeof value === "string") {
-    safeKey = "string_unsafe";
-    block = text(value);
-  } else {
-    // Assuming it is a block
-    safeKey = "block_safe";
-    block = value;
-  }
-  return toggler(safeKey, block);
-}
-
-let boundFunctions = new WeakMap();
-
-function bind(ctx: any, fn: Function): Function {
-  let component = ctx.__owl__.component;
-  let boundFnMap = boundFunctions.get(component);
-  if (!boundFnMap) {
-    boundFnMap = new WeakMap();
-    boundFunctions.set(component, boundFnMap);
-  }
-  let boundFn = boundFnMap.get(fn);
-  if (!boundFn) {
-    boundFn = fn.bind(component);
-    boundFnMap.set(fn, boundFn);
-  }
-  return boundFn;
-}
-
-type RefMap = { [key: string]: HTMLElement | null };
-type RefSetter = (el: HTMLElement | null) => void;
-
-function multiRefSetter(refs: RefMap, name: string): RefSetter {
-  let count = 0;
-  return (el) => {
-    if (el) {
-      count++;
-      if (count > 1) {
-        throw new Error("Cannot have 2 elements with same ref name at the same time");
-      }
-    }
-    if (count === 0 || el) {
-      refs[name] = el;
-    }
-  };
-}
-
-export const helpers = {
-  withDefault,
-  zero: Symbol("zero"),
-  isBoundary,
-  callSlot,
-  capture,
-  withKey,
-  prepareList,
-  setContextValue,
-  multiRefSetter,
-  shallowEqual,
-  toNumber,
-  validateProps,
-  LazyValue,
-  safeOutput,
-  bind,
-  createCatcher,
-};

src/blockdom/event_catcher.ts

@@ -1,89 +0,0 @@
-import { createEventHandler } from "./events";
-import type { VNode } from "./index";
-
-type EventsSpec = { [name: string]: number };
-
-type Catcher = (child: VNode, handlers: any[]) => VNode;
-
-export function createCatcher(eventsSpec: EventsSpec): Catcher {
-  let setupFns: any[] = [];
-  let removeFns: any[] = [];
-  for (let name in eventsSpec) {
-    let index = eventsSpec[name];
-    let { setup, remove } = createEventHandler(name);
-    setupFns[index] = setup;
-    removeFns[index] = remove;
-  }
-  let n = setupFns.length;
-
-  class VCatcher {
-    child: VNode;
-    handlers: any[];
-
-    parentEl?: HTMLElement | undefined;
-    afterNode: Node | null = null;
-
-    constructor(child: VNode, handlers: any[]) {
-      this.child = child;
-      this.handlers = handlers;
-    }
-
-    mount(parent: HTMLElement, afterNode: Node | null) {
-      this.parentEl = parent;
-      this.afterNode = afterNode;
-      this.child.mount(parent, afterNode);
-      for (let i = 0; i < n; i++) {
-        let origFn = this.handlers[i][0];
-        const self = this;
-        this.handlers[i][0] = function (ev: any) {
-          const target = ev.target;
-          let currentNode: any = self.child.firstNode();
-          const afterNode = self.afterNode;
-          while (currentNode !== afterNode) {
-            if (currentNode.contains(target)) {
-              return origFn.call(this, ev);
-            }
-            currentNode = currentNode.nextSibling;
-          }
-        };
-        setupFns[i].call(parent, this.handlers[i]);
-      }
-    }
-
-    moveBefore(other: VCatcher | null, afterNode: Node | null) {
-      this.afterNode = null;
-      this.child.moveBefore(other ? other.child : null, afterNode);
-    }
-
-    patch(other: VCatcher, withBeforeRemove: boolean) {
-      if (this === other) {
-        return;
-      }
-      this.handlers = other.handlers;
-      this.child.patch(other.child, withBeforeRemove);
-    }
-
-    beforeRemove() {
-      this.child.beforeRemove();
-    }
-
-    remove() {
-      for (let i = 0; i < n; i++) {
-        removeFns[i].call(this.parentEl!);
-      }
-      this.child.remove();
-    }
-
-    firstNode(): Node | undefined {
-      return this.child.firstNode();
-    }
-
-    toString(): string {
-      return this.child.toString();
-    }
-  }
-
-  return function (child: VNode, handlers: any[]): VNode<VCatcher> {
-    return new VCatcher(child, handlers);
-  };
-}

src/compiler/index.ts

@@ -1,10 +1,11 @@
-import type { BDom } from "../blockdom";
+import type { TemplateSet } from "../runtime/template_set";
+import type { BDom } from "../runtime/blockdom";
 import { CodeGenerator, Config } from "./code_generator";
 import { parse } from "./parser";
 
 export type Template = (context: any, vnode: any, key?: string) => BDom;
 
-export type TemplateFunction = (blocks: any, utils: any) => Template;
+export type TemplateFunction = (app: TemplateSet, bdom: any, helpers: any) => Template;
 
 interface CompileOptions extends Config {
   name?: string;
@@ -26,5 +27,5 @@ export function compile(
   const codeGenerator = new CodeGenerator(ast, { ...options, hasSafeContext });
   const code = codeGenerator.generateCode();
   // template function
-  return new Function("bdom, helpers", code) as TemplateFunction;
+  return new Function("app, bdom, helpers", code) as TemplateFunction;
 }

src/compiler/inline_expressions.ts

@@ -1,3 +1,5 @@
+import { OwlError } from "../runtime/error_handling";
+
 /**
  * Owl QWeb Expression Parser
  *
@@ -26,7 +28,7 @@
 //------------------------------------------------------------------------------
 
 const RESERVED_WORDS =
-  "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,this,eval,void,Math,RegExp,Array,Object,Date".split(
+  "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,eval,void,Math,RegExp,Array,Object,Date".split(
     ","
   );
 
@@ -85,8 +87,9 @@ const STATIC_TOKEN_MAP: { [key: string]: TKind } = Object.assign(Object.create(n
 });
 
 // note that the space after typeof is relevant. It makes sure that the formatted
-// expression has a space after typeof
-const OPERATORS = "...,.,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%,typeof ,=>,=,;,in ".split(",");
+// expression has a space after typeof. Currently we don't support delete and void
+const OPERATORS =
+  "...,.,===,==,+,!==,!=,!,||,&&,>=,>,<=,<,?,-,*,/,%,typeof ,=>,=,;,in ,new ,|,&,^,~".split(",");
 
 type Tokenizer = (expr: string) => Token | false;
 
@@ -105,14 +108,14 @@ let tokenizeString: Tokenizer = function (expr) {
       i++;
       cur = expr[i];
       if (!cur) {
-        throw new Error("Invalid expression");
+        throw new OwlError("Invalid expression");
       }
       s += cur;
     }
     i++;
   }
   if (expr[i] !== start) {
-    throw new Error("Invalid expression");
+    throw new OwlError("Invalid expression");
   }
   s += start;
   if (start === "`") {
@@ -222,7 +225,7 @@ export function tokenize(expr: string): Token[] {
     error = e; // Silence all errors and throw a generic error below
   }
   if (current.length || error) {
-    throw new Error(`Tokenizer error: could not tokenize \`${expr}\``);
+    throw new OwlError(`Tokenizer error: could not tokenize \`${expr}\``);
   }
   return result;
 }
@@ -344,21 +347,29 @@ export function compileExprToArray(expr: string): Token[] {
   return tokens;
 }
 
+// Leading spaces are trimmed during tokenization, so they need to be added back for some values
+const paddedValues = new Map([["in ", " in "]]);
+
 export function compileExpr(expr: string): string {
   return compileExprToArray(expr)
-    .map((t) => t.value)
+    .map((t) => paddedValues.get(t.value) || t.value)
     .join("");
 }
 
-export const INTERP_REGEXP = /\{\{.*?\}\}/g;
-const INTERP_GROUP_REGEXP = /\{\{.*?\}\}/g;
+export const INTERP_REGEXP = /\{\{.*?\}\}|\#\{.*?\}/g;
 
-export function interpolate(s: string): string {
+export function replaceDynamicParts(s: string, replacer: (s: string) => string) {
   let matches = s.match(INTERP_REGEXP);
   if (matches && matches[0].length === s.length) {
-    return `(${compileExpr(s.slice(2, -2))})`;
+    return `(${replacer(s.slice(2, matches[0][0] === "{" ? -2 : -1))})`;
   }
 
-  let r = s.replace(INTERP_GROUP_REGEXP, (s) => "${" + compileExpr(s.slice(2, -2)) + "}");
+  let r = s.replace(
+    INTERP_REGEXP,
+    (s) => "${" + replacer(s.slice(2, s[0] === "{" ? -2 : -1)) + "}"
+  );
   return "`" + r + "`";
 }
+export function interpolate(s: string): string {
+  return replaceDynamicParts(s, compileExpr);
+}

src/compiler/parser.ts

@@ -1,3 +1,5 @@
+import { OwlError } from "../runtime/error_handling";
+
 // -----------------------------------------------------------------------------
 // AST Type definition
 // -----------------------------------------------------------------------------
@@ -115,10 +117,11 @@ export interface ASTTCall {
   type: ASTType.TCall;
   name: string;
   body: AST[] | null;
+  context: string | null;
 }
 
 interface SlotDefinition {
-  content: AST;
+  content: AST | null;
   scope: string | null;
   on: EventHandlers | null;
   attrs: Attrs | null;
@@ -258,16 +261,12 @@ function parseTNode(node: Element, ctx: ParsingContext): AST | null {
 // Text and Comment Nodes
 // -----------------------------------------------------------------------------
 const lineBreakRE = /[\r\n]/;
-const whitespaceRE = /\s+/g;
 
 function parseTextCommentNode(node: Node, ctx: ParsingContext): AST | null {
   if (node.nodeType === Node.TEXT_NODE) {
     let value = node.textContent || "";
-    if (!ctx.inPreTag) {
-      if (lineBreakRE.test(value) && !value.trim()) {
-        return null;
-      }
-      value = value.replace(whitespaceRE, " ");
+    if (!ctx.inPreTag && lineBreakRE.test(value) && !value.trim()) {
+      return null;
     }
 
     return { type: ASTType.Text, value };
@@ -318,7 +317,7 @@ function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
     return null;
   }
   if (tagName.startsWith("block-")) {
-    throw new Error(`Invalid tag name: '${tagName}'`);
+    throw new OwlError(`Invalid tag name: '${tagName}'`);
   }
   ctx = Object.assign({}, ctx);
   if (tagName === "pre") {
@@ -339,13 +338,15 @@ function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
     const value = node.getAttribute(attr)!;
     if (attr.startsWith("t-on")) {
       if (attr === "t-on") {
-        throw new Error("Missing event name with t-on directive");
+        throw new OwlError("Missing event name with t-on directive");
       }
       on = on || {};
       on[attr.slice(5)] = value;
     } else if (attr.startsWith("t-model")) {
       if (!["input", "select", "textarea"].includes(tagName)) {
-        throw new Error("The t-model directive only works with <input>, <textarea> and <select>");
+        throw new OwlError(
+          "The t-model directive only works with <input>, <textarea> and <select>"
+        );
       }
 
       let baseExpr, expr;
@@ -358,7 +359,7 @@ function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
         baseExpr = value.slice(0, index);
         expr = value.slice(index + 1, -1);
       } else {
-        throw new Error(`Invalid t-model expression: "${value}" (it should be assignable)`);
+        throw new OwlError(`Invalid t-model expression: "${value}" (it should be assignable)`);
       }
 
       const typeAttr = node.getAttribute("type");
@@ -389,10 +390,10 @@ function parseDOMNode(node: Element, ctx: ParsingContext): AST | null {
         ctx.tModelInfo = model;
       }
     } else if (attr.startsWith("block-")) {
-      throw new Error(`Invalid attribute: '${attr}'`);
+      throw new OwlError(`Invalid attribute: '${attr}'`);
     } else if (attr !== "t-name") {
       if (attr.startsWith("t-") && !attr.startsWith("t-att")) {
-        throw new Error(`Unknown QWeb directive: '${attr}'`);
+        throw new OwlError(`Unknown QWeb directive: '${attr}'`);
       }
       const tModel = ctx.tModelInfo;
       if (tModel && ["t-att-value", "t-attf-value"].includes(attr)) {
@@ -446,7 +447,7 @@ function parseTEscNode(node: Element, ctx: ParsingContext): AST | null {
     };
   }
   if (ast.type === ASTType.TComponent) {
-    throw new Error("t-esc is not supported on Component nodes");
+    throw new OwlError("t-esc is not supported on Component nodes");
   }
   return tesc;
 }
@@ -502,7 +503,7 @@ function parseTForEach(node: Element, ctx: ParsingContext): AST | null {
   node.removeAttribute("t-as");
   const key = node.getAttribute("t-key");
   if (!key) {
-    throw new Error(
+    throw new OwlError(
       `"Directive t-foreach should always be used with a t-key!" (expression: t-foreach="${collection}" t-as="${elem}")`
     );
   }
@@ -557,11 +558,13 @@ function parseTCall(node: Element, ctx: ParsingContext): AST | null {
     return null;
   }
   const subTemplate = node.getAttribute("t-call")!;
-
+  const context = node.getAttribute("t-call-context");
   node.removeAttribute("t-call");
+  node.removeAttribute("t-call-context");
+
   if (node.tagName !== "t") {
     const ast = parseNode(node, ctx);
-    const tcall: AST = { type: ASTType.TCall, name: subTemplate, body: null };
+    const tcall: AST = { type: ASTType.TCall, name: subTemplate, body: null, context };
     if (ast && ast.type === ASTType.DomNode) {
       ast.content = [tcall];
       return ast;
@@ -579,6 +582,7 @@ function parseTCall(node: Element, ctx: ParsingContext): AST | null {
     type: ASTType.TCall,
     name: subTemplate,
     body: body.length ? body : null,
+    context,
   };
 }
 
@@ -682,7 +686,9 @@ function parseComponent(node: Element, ctx: ParsingContext): AST | null {
   let isDynamic = node.hasAttribute("t-component");
 
   if (isDynamic && name !== "t") {
-    throw new Error(`Directive 't-component' can only be used on <t> nodes (used on a <${name}>)`);
+    throw new OwlError(
+      `Directive 't-component' can only be used on <t> nodes (used on a <${name}>)`
+    );
   }
 
   if (!(firstLetter === firstLetter.toUpperCase() || isDynamic)) {
@@ -709,7 +715,7 @@ function parseComponent(node: Element, ctx: ParsingContext): AST | null {
         on[name.slice(5)] = value;
       } else {
         const message = directiveErrorMap.get(name.split("-").slice(0, 2).join("-"));
-        throw new Error(message || `unsupported directive on Component: ${name}`);
+        throw new OwlError(message || `unsupported directive on Component: ${name}`);
       }
     } else {
       props = props || {};
@@ -725,7 +731,7 @@ function parseComponent(node: Element, ctx: ParsingContext): AST | null {
     const slotNodes = Array.from(clone.querySelectorAll("[t-set-slot]"));
     for (let slotNode of slotNodes) {
       if (slotNode.tagName !== "t") {
-        throw new Error(
+        throw new OwlError(
           `Directive 't-set-slot' can only be used on <t> nodes (used on a <${slotNode.tagName}>)`
         );
       }
@@ -749,32 +755,31 @@ function parseComponent(node: Element, ctx: ParsingContext): AST | null {
       slotNode.removeAttribute("t-set-slot");
       slotNode.remove();
       const slotAst = parseNode(slotNode, ctx);
-      if (slotAst) {
-        let on: SlotDefinition["on"] = null;
-        let attrs: Attrs | null = null;
-        let scope: string | null = null;
-        for (let attributeName of slotNode.getAttributeNames()) {
-          const value = slotNode.getAttribute(attributeName)!;
-          if (attributeName === "t-slot-scope") {
-            scope = value;
-            continue;
-          } else if (attributeName.startsWith("t-on-")) {
-            on = on || {};
-            on[attributeName.slice(5)] = value;
-          } else {
-            attrs = attrs || {};
-            attrs[attributeName] = value;
-          }
+      let on: SlotDefinition["on"] = null;
+      let attrs: Attrs | null = null;
+      let scope: string | null = null;
+      for (let attributeName of slotNode.getAttributeNames()) {
+        const value = slotNode.getAttribute(attributeName)!;
+        if (attributeName === "t-slot-scope") {
+          scope = value;
+          continue;
+        } else if (attributeName.startsWith("t-on-")) {
+          on = on || {};
+          on[attributeName.slice(5)] = value;
+        } else {
+          attrs = attrs || {};
+          attrs[attributeName] = value;
         }
-        slots = slots || {};
-        slots[name] = { content: slotAst, on, attrs, scope };
       }
+      slots = slots || {};
+      slots[name] = { content: slotAst, on, attrs, scope };
     }
 
     // default slot
     const defaultContent = parseChildNodes(clone, ctx);
-    if (defaultContent) {
-      slots = slots || {};
+    slots = slots || {};
+    // t-set-slot="default" has priority over content
+    if (defaultContent && !slots.default) {
       slots.default = { content: defaultContent, on, attrs: null, scope: defaultSlotScope };
     }
   }
@@ -902,7 +907,7 @@ function normalizeTIf(el: Element) {
     let nattr = (name: string) => +!!node.getAttribute(name);
     if (prevElem && (pattr("t-if") || pattr("t-elif"))) {
       if (pattr("t-foreach")) {
-        throw new Error(
+        throw new OwlError(
           "t-if cannot stay at the same level as t-foreach when using t-elif or t-else"
         );
       }
@@ -911,19 +916,19 @@ function normalizeTIf(el: Element) {
           return a + b;
         }) > 1
       ) {
-        throw new Error("Only one conditional branching directive is allowed per node");
+        throw new OwlError("Only one conditional branching directive is allowed per node");
       }
       // All text (with only spaces) and comment nodes (nodeType 8) between
       // branch nodes are removed
       let textNode;
       while ((textNode = node.previousSibling) !== prevElem) {
         if (textNode!.nodeValue!.trim().length && textNode!.nodeType !== 8) {
-          throw new Error("text is not allowed between branching directives");
+          throw new OwlError("text is not allowed between branching directives");
         }
         textNode!.remove();
       }
     } else {
-      throw new Error(
+      throw new OwlError(
         "t-elif and t-else directives must be preceded by a t-if or t-elif directive"
       );
     }
@@ -944,7 +949,7 @@ function normalizeTEsc(el: Element) {
   );
   for (const el of elements) {
     if (el.childNodes.length) {
-      throw new Error("Cannot have t-esc on a component that already has content");
+      throw new OwlError("Cannot have t-esc on a component that already has content");
     }
     const value = el.getAttribute("t-esc");
     el.removeAttribute("t-esc");
@@ -998,7 +1003,7 @@ function parseXML(xml: string): XMLDocument {
         }
       }
     }
-    throw new Error(msg);
+    throw new OwlError(msg);
   }
 
   return doc;

src/component/props_validation.ts

@@ -1,150 +0,0 @@
-import { ComponentConstructor } from "./component";
-
-/**
- * Apply default props (only top level).
- *
- * Note that this method does modify in place the props
- */
-export function applyDefaultProps<P>(props: P, ComponentClass: ComponentConstructor<P>) {
-  const defaultProps = ComponentClass.defaultProps;
-  if (defaultProps) {
-    for (let propName in defaultProps) {
-      if ((props as any)[propName] === undefined) {
-        (props as any)[propName] = defaultProps[propName];
-      }
-    }
-  }
-}
-
-//------------------------------------------------------------------------------
-// Prop validation helper
-//------------------------------------------------------------------------------
-function getPropDescription(staticProps: any) {
-  if (staticProps instanceof Array) {
-    return Object.fromEntries(
-      staticProps.map((p) => (p.endsWith("?") ? [p.slice(0, -1), false] : [p, true]))
-    );
-  }
-  return staticProps || { "*": true };
-}
-
-/**
- * Validate the component props (or next props) against the (static) props
- * description.  This is potentially an expensive operation: it may needs to
- * visit recursively the props and all the children to check if they are valid.
- * This is why it is only done in 'dev' mode.
- */
-export function validateProps<P>(name: string | ComponentConstructor<P>, props: P, parent?: any) {
-  const ComponentClass =
-    typeof name !== "string"
-      ? name
-      : (parent.constructor.components[name] as ComponentConstructor<P> | undefined);
-
-  if (!ComponentClass) {
-    // this is an error, wrong component. We silently return here instead so the
-    // error is triggered by the usual path ('component' function)
-    return;
-  }
-  applyDefaultProps(props, ComponentClass);
-
-  const defaultProps = ComponentClass.defaultProps || {};
-  let propsDef = getPropDescription(ComponentClass.props);
-  const allowAdditionalProps = "*" in propsDef;
-
-  for (let propName in propsDef) {
-    if (propName === "*") {
-      continue;
-    }
-    const propDef = propsDef[propName];
-    let isMandatory = !!propDef;
-    if (typeof propDef === "object" && "optional" in propDef) {
-      isMandatory = !propDef.optional;
-    }
-    if (isMandatory && propName in defaultProps) {
-      throw new Error(
-        `A default value cannot be defined for a mandatory prop (name: '${propName}', component: ${ComponentClass.name})`
-      );
-    }
-    if ((props as any)[propName] === undefined) {
-      if (isMandatory) {
-        throw new Error(`Missing props '${propName}' (component '${ComponentClass.name}')`);
-      } else {
-        continue;
-      }
-    }
-    let isValid;
-    try {
-      isValid = isValidProp((props as any)[propName], propDef);
-    } catch (e) {
-      (e as Error).message = `Invalid prop '${propName}' in component ${ComponentClass.name} (${
-        (e as Error).message
-      })`;
-      throw e;
-    }
-    if (!isValid) {
-      throw new Error(`Invalid Prop '${propName}' in component '${ComponentClass.name}'`);
-    }
-  }
-  if (!allowAdditionalProps) {
-    for (let propName in props) {
-      if (!(propName in propsDef)) {
-        throw new Error(`Unknown prop '${propName}' given to component '${ComponentClass.name}'`);
-      }
-    }
-  }
-}
-
-/**
- * Check if an invidual prop value matches its (static) prop definition
- */
-function isValidProp(prop: any, propDef: any): boolean {
-  if (propDef === true) {
-    return true;
-  }
-  if (typeof propDef === "function") {
-    // Check if a value is constructed by some Constructor.  Note that there is a
-    // slight abuse of language: we want to consider primitive values as well.
-    //
-    // So, even though 1 is not an instance of Number, we want to consider that
-    // it is valid.
-    if (typeof prop === "object") {
-      return prop instanceof propDef;
-    }
-    return typeof prop === propDef.name.toLowerCase();
-  } else if (propDef instanceof Array) {
-    // If this code is executed, this means that we want to check if a prop
-    // matches at least one of its descriptor.
-    let result = false;
-    for (let i = 0, iLen = propDef.length; i < iLen; i++) {
-      result = result || isValidProp(prop, propDef[i]);
-    }
-    return result;
-  }
-  // propsDef is an object
-  if (propDef.optional && prop === undefined) {
-    return true;
-  }
-  let result = propDef.type ? isValidProp(prop, propDef.type) : true;
-  if (propDef.validate) {
-    result = result && propDef.validate(prop);
-  }
-  if (propDef.type === Array && propDef.element) {
-    for (let i = 0, iLen = prop.length; i < iLen; i++) {
-      result = result && isValidProp(prop[i], propDef.element);
-    }
-  }
-  if (propDef.type === Object && propDef.shape) {
-    const shape = propDef.shape;
-    for (let key in shape) {
-      result = result && isValidProp(prop[key], shape[key]);
-    }
-    if (result) {
-      for (let propName in prop) {
-        if (!(propName in shape)) {
-          throw new Error(`unknown prop '${propName}'`);
-        }
-      }
-    }
-  }
-  return result;
-}

src/component/scheduler.ts

@@ -1,77 +0,0 @@
-import { fibersInError } from "./error_handling";
-import { Fiber, RootFiber } from "./fibers";
-import { STATUS } from "./status";
-
-// -----------------------------------------------------------------------------
-//  Scheduler
-// -----------------------------------------------------------------------------
-
-export class Scheduler {
-  // capture the value of requestAnimationFrame as soon as possible, to avoid
-  // interactions with other code, such as test frameworks that override them
-  static requestAnimationFrame = window.requestAnimationFrame.bind(window);
-  tasks: Set<RootFiber> = new Set();
-  isRunning: boolean = false;
-  requestAnimationFrame: Window["requestAnimationFrame"];
-
-  constructor() {
-    this.requestAnimationFrame = Scheduler.requestAnimationFrame;
-  }
-
-  start() {
-    this.isRunning = true;
-    this.scheduleTasks();
-  }
-
-  stop() {
-    this.isRunning = false;
-  }
-
-  addFiber(fiber: Fiber) {
-    this.tasks.add(fiber.root!);
-    if (!this.isRunning) {
-      this.start();
-    }
-  }
-
-  /**
-   * Process all current tasks. This only applies to the fibers that are ready.
-   * Other tasks are left unchanged.
-   */
-  flush() {
-    this.tasks.forEach((fiber) => {
-      if (fiber.root !== fiber) {
-        this.tasks.delete(fiber);
-        return;
-      }
-      const hasError = fibersInError.has(fiber);
-      if (hasError && fiber.counter !== 0) {
-        this.tasks.delete(fiber);
-        return;
-      }
-      if (fiber.node.status === STATUS.DESTROYED) {
-        this.tasks.delete(fiber);
-        return;
-      }
-
-      if (fiber.counter === 0) {
-        if (!hasError) {
-          fiber.complete();
-        }
-        this.tasks.delete(fiber);
-      }
-    });
-    if (this.tasks.size === 0) {
-      this.stop();
-    }
-  }
-
-  scheduleTasks() {
-    this.requestAnimationFrame(() => {
-      this.flush();
-      if (this.isRunning) {
-        this.scheduleTasks();
-      }
-    });
-  }
-}

src/index.ts

@@ -1,56 +1,16 @@
-import {
-  config,
-  createBlock,
-  html,
-  list,
-  mount as blockMount,
-  multi,
-  patch,
-  remove,
-  text,
-  toggler,
-  comment,
-} from "./blockdom";
-import { mainEventHandler } from "./component/handler";
-export type { Reactive } from "./reactivity";
+import { TemplateSet } from "./runtime/template_set";
+import { compile } from "./compiler";
 
-config.shouldNormalizeDom = false;
-config.mainEventHandler = mainEventHandler;
+export * from "./runtime";
 
-export const blockDom = {
-  config,
-  // bdom entry points
-  mount: blockMount,
-  patch,
-  remove,
-  // bdom block types
-  list,
-  multi,
-  text,
-  toggler,
-  createBlock,
-  html,
-  comment,
+TemplateSet.prototype._compileTemplate = function _compileTemplate(
+  name: string,
+  template: string | Element
+) {
+  return compile(template, {
+    name,
+    dev: this.dev,
+    translateFn: this.translateFn,
+    translatableAttributes: this.translatableAttributes,
+  });
 };
-
-export { App, mount } from "./app/app";
-export { Component } from "./component/component";
-export { useComponent, useState } from "./component/component_node";
-export { status } from "./component/status";
-export { reactive, markRaw, toRaw } from "./reactivity";
-export { useEffect, useEnv, useExternalListener, useRef, useChildSubEnv, useSubEnv } from "./hooks";
-export { EventBus, whenReady, loadFile, markup, xml } from "./utils";
-export {
-  onWillStart,
-  onMounted,
-  onWillUnmount,
-  onWillUpdateProps,
-  onWillPatch,
-  onPatched,
-  onWillRender,
-  onRendered,
-  onWillDestroy,
-  onError,
-} from "./component/lifecycle_hooks";
-
-export const __info__ = {};

src/portal.ts

@@ -1,75 +0,0 @@
-import { onWillUnmount } from "./component/lifecycle_hooks";
-import { xml } from "./utils";
-import { BDom, text, VNode } from "./blockdom";
-import { Component } from "./component/component";
-
-const VText: any = text("").constructor;
-
-class VPortal extends VText implements Partial<VNode<VPortal>> {
-  //   selector: string;
-  realBDom: BDom | null;
-  target: HTMLElement | null = null;
-
-  constructor(selector: string, realBDom: BDom) {
-    super("");
-    this.selector = selector;
-    this.realBDom = realBDom;
-  }
-  mount(parent: HTMLElement, anchor: ChildNode) {
-    super.mount(parent, anchor);
-    this.target = document.querySelector(this.selector) as any;
-    if (!this.target) {
-      let el: any = this.el;
-      while (el && el.parentElement instanceof HTMLElement) {
-        el = el.parentElement;
-      }
-      this.target = el && el.querySelector(this.selector);
-      if (!this.target) {
-        throw new Error("invalid portal target");
-      }
-    }
-    this.realBDom!.mount(this.target!, null);
-  }
-
-  beforeRemove() {
-    this.realBDom!.beforeRemove();
-  }
-  remove() {
-    if (this.realBDom) {
-      super.remove();
-      this.realBDom!.remove();
-      this.realBDom = null;
-    }
-  }
-
-  patch(other: VPortal) {
-    super.patch(other);
-    if (this.realBDom) {
-      this.realBDom.patch(other.realBDom!, true);
-    } else {
-      this.realBDom = other.realBDom;
-      this.realBDom!.mount(this.target!, null);
-    }
-  }
-}
-
-export class Portal extends Component {
-  static template = xml`<t t-slot="default"/>`;
-  static props = {
-    target: {
-      type: String,
-    },
-    slots: true,
-  };
-
-  setup() {
-    const node = this.__owl__;
-    const renderFn = node.renderFn;
-    node.renderFn = () => new VPortal(this.props.target, renderFn());
-    onWillUnmount(() => {
-      if (node.bdom) {
-        node.bdom.remove();
-      }
-    });
-  }
-}

src/runtime/app.ts

@@ -0,0 +1,228 @@
+import { version } from "../version";
+import { Component, ComponentConstructor, Props } from "./component";
+import { ComponentNode } from "./component_node";
+import { nodeErrorHandlers, OwlError, handleError } from "./error_handling";
+import { Fiber, RootFiber, MountOptions } from "./fibers";
+import { Scheduler } from "./scheduler";
+import { validateProps } from "./template_helpers";
+import { TemplateSet, TemplateSetConfig } from "./template_set";
+import { validateTarget } from "./utils";
+
+// reimplement dev mode stuff see last change in 0f7a8289a6fb8387c3c1af41c6664b2a8448758f
+
+export interface Env {
+  [key: string]: any;
+}
+
+export interface AppConfig<P, E> extends TemplateSetConfig {
+  name?: string;
+  props?: P;
+  env?: E;
+  test?: boolean;
+  warnIfNoStaticProps?: boolean;
+}
+
+let hasBeenLogged = false;
+
+export const DEV_MSG = () => {
+  const hash = (window as any).owl ? (window as any).owl.__info__.hash : "master";
+
+  return `Owl is running in 'dev' mode.
+
+This is not suitable for production use.
+See https://github.com/odoo/owl/blob/${hash}/doc/reference/app.md#configuration for more information.`;
+};
+
+declare global {
+  interface Window {
+    __OWL_DEVTOOLS__: {
+      apps: Set<App>;
+      Fiber: typeof Fiber;
+      RootFiber: typeof RootFiber;
+    };
+  }
+}
+
+window.__OWL_DEVTOOLS__ ||= {
+  apps: new Set<App>(),
+  Fiber: Fiber,
+  RootFiber: RootFiber,
+};
+
+export class App<
+  T extends abstract new (...args: any) => any = any,
+  P extends object = any,
+  E = any
+> extends TemplateSet {
+  static validateTarget = validateTarget;
+  static version = version;
+
+  name: string;
+  Root: ComponentConstructor<P, E>;
+  props: P;
+  env: E;
+  scheduler = new Scheduler();
+  root: ComponentNode<P, E> | null = null;
+  warnIfNoStaticProps: boolean;
+
+  constructor(Root: ComponentConstructor<P, E>, config: AppConfig<P, E> = {}) {
+    super(config);
+    this.name = config.name || "";
+    this.Root = Root;
+    window.__OWL_DEVTOOLS__.apps.add(this);
+    if (config.test) {
+      this.dev = true;
+    }
+    this.warnIfNoStaticProps = config.warnIfNoStaticProps || false;
+    if (this.dev && !config.test && !hasBeenLogged) {
+      console.info(DEV_MSG());
+      hasBeenLogged = true;
+    }
+    const env = config.env || {};
+    const descrs = Object.getOwnPropertyDescriptors(env);
+    this.env = Object.freeze(Object.create(Object.getPrototypeOf(env), descrs));
+    this.props = config.props || ({} as P);
+  }
+
+  mount(target: HTMLElement, options?: MountOptions): Promise<Component<P, E> & InstanceType<T>> {
+    App.validateTarget(target);
+    if (this.dev) {
+      validateProps(this.Root, this.props, { __owl__: { app: this } });
+    }
+    const node = this.makeNode(this.Root, this.props);
+    const prom = this.mountNode(node, target, options);
+    this.root = node;
+    return prom;
+  }
+
+  makeNode(Component: ComponentConstructor, props: any): ComponentNode {
+    return new ComponentNode(Component, props, this, null, null);
+  }
+
+  mountNode(node: ComponentNode, target: HTMLElement, options?: MountOptions) {
+    const promise: any = new Promise((resolve, reject) => {
+      let isResolved = false;
+      // manually set a onMounted callback.
+      // that way, we are independant from the current node.
+      node.mounted.push(() => {
+        resolve(node.component);
+        isResolved = true;
+      });
+
+      // Manually add the last resort error handler on the node
+      let handlers = nodeErrorHandlers.get(node);
+      if (!handlers) {
+        handlers = [];
+        nodeErrorHandlers.set(node, handlers);
+      }
+      handlers.unshift((e) => {
+        if (!isResolved) {
+          reject(e);
+        }
+        throw e;
+      });
+    });
+    node.mountComponent(target, options);
+    return promise;
+  }
+
+  destroy() {
+    if (this.root) {
+      this.scheduler.flush();
+      this.root.destroy();
+    }
+    window.__OWL_DEVTOOLS__.apps.delete(this);
+  }
+
+  createComponent<P extends Props>(
+    name: string | null,
+    isStatic: boolean,
+    hasSlotsProp: boolean,
+    hasDynamicPropList: boolean,
+    propList: string[]
+  ) {
+    const isDynamic = !isStatic;
+    let arePropsDifferent: (p1: Object, p2: Object) => boolean;
+    const hasNoProp = propList.length === 0;
+    if (hasSlotsProp) {
+      arePropsDifferent = (_1, _2) => true;
+    } else if (hasDynamicPropList) {
+      arePropsDifferent = function (props1: Props, props2: Props) {
+        for (let k in props1) {
+          if (props1[k] !== props2[k]) {
+            return true;
+          }
+        }
+        return Object.keys(props1).length !== Object.keys(props2).length;
+      };
+    } else if (hasNoProp) {
+      arePropsDifferent = (_1: any, _2: any) => false;
+    } else {
+      arePropsDifferent = function (props1: Props, props2: Props) {
+        for (let p of propList) {
+          if (props1[p] !== props2[p]) {
+            return true;
+          }
+        }
+        return false;
+      };
+    }
+
+    const updateAndRender = ComponentNode.prototype.updateAndRender;
+    const initiateRender = ComponentNode.prototype.initiateRender;
+
+    return (props: P, key: string, ctx: ComponentNode, parent: any, C: any) => {
+      let children = ctx.children;
+      let node: any = children[key];
+      if (isDynamic && node && node.component.constructor !== C) {
+        node = undefined;
+      }
+      const parentFiber = ctx.fiber!;
+      if (node) {
+        if (arePropsDifferent(node.props, props) || parentFiber.deep || node.forceNextRender) {
+          node.forceNextRender = false;
+          updateAndRender.call(node, props, parentFiber);
+        }
+      } else {
+        // new component
+        if (isStatic) {
+          const components = parent.constructor.components;
+          if (!components) {
+            throw new OwlError(
+              `Cannot find the definition of component "${name}", missing static components key in parent`
+            );
+          }
+          C = components[name as any];
+          if (!C) {
+            throw new OwlError(`Cannot find the definition of component "${name}"`);
+          } else if (!(C.prototype instanceof Component)) {
+            throw new OwlError(
+              `"${name}" is not a Component. It must inherit from the Component class`
+            );
+          }
+        }
+        node = new ComponentNode(C, props, this, ctx, key);
+        children[key] = node;
+        initiateRender.call(node, new Fiber(node, parentFiber));
+      }
+      parentFiber.childrenMap[key] = node;
+      return node;
+    };
+  }
+
+  handleError(...args: Parameters<typeof handleError>) {
+    return handleError(...args);
+  }
+}
+
+export async function mount<
+  T extends abstract new (...args: any) => any = any,
+  P extends object = any,
+  E = any
+>(
+  C: T & ComponentConstructor<P, E>,
+  target: HTMLElement,
+  config: AppConfig<P, E> & MountOptions = {}
+): Promise<Component<P, E> & InstanceType<T>> {
+  return new App(C, config).mount(target, config);
+}

src/runtime/blockdom/attributes.ts

@@ -93,6 +93,10 @@ function toClassObj(expr: string | number | { [c: string]: any }) {
       for (let key in expr as any) {
         const value = (expr as any)[key];
         if (value) {
+          key = trim.call(key);
+          if (!key) {
+            continue;
+          }
           const words = split.call(key, wordRegexp);
           for (let word of words) {
             result[word] = value;
@@ -136,32 +140,3 @@ export function updateClass(this: HTMLElement, val: any, oldVal: any) {
     }
   }
 }
-
-export function makePropSetter(name: string): Setter<HTMLElement> {
-  return function setProp(this: HTMLElement, value: any) {
-    (this as any)[name] = value || "";
-  };
-}
-
-export function isProp(tag: string, key: string): boolean {
-  switch (tag) {
-    case "input":
-      return (
-        key === "checked" ||
-        key === "indeterminate" ||
-        key === "value" ||
-        key === "readonly" ||
-        key === "disabled"
-      );
-    case "option":
-      return key === "selected" || key === "disabled";
-    case "textarea":
-      return key === "value" || key === "readonly" || key === "disabled";
-    case "select":
-      return key === "value" || key === "disabled";
-    case "button":
-    case "optgroup":
-      return key === "disabled";
-  }
-  return false;
-}

src/runtime/blockdom/block_compiler.ts

@@ -1,12 +1,5 @@
-import {
-  attrsSetter,
-  attrsUpdater,
-  createAttrUpdater,
-  isProp,
-  makePropSetter,
-  setClass,
-  updateClass,
-} from "./attributes";
+import { OwlError } from "../error_handling";
+import { attrsSetter, attrsUpdater, createAttrUpdater, setClass, updateClass } from "./attributes";
 import { config } from "./config";
 import { createEventHandler } from "./events";
 import type { VNode } from "./index";
@@ -24,6 +17,13 @@ const nodeGetNextSibling = getDescriptor(nodeProto, "nextSibling").get!;
 
 const NO_OP = () => {};
 
+function makePropSetter(name: string): Setter<HTMLElement> {
+  return function setProp(this: HTMLElement, value: any) {
+    // support 0, fallback to empty string for other falsy values
+    (this as any)[name] = value === 0 ? 0 : value ? value.valueOf() : "";
+  };
+}
+
 // -----------------------------------------------------------------------------
 // Main compiler code
 // -----------------------------------------------------------------------------
@@ -100,7 +100,7 @@ function normalizeNode(node: HTMLElement | Text) {
 interface DynamicInfo {
   idx: number;
   refIdx?: number;
-  type: "text" | "child" | "handler" | "attribute" | "attributes" | "ref";
+  type: "text" | "child" | "handler" | "attribute" | "attributes" | "property" | "ref";
   isOnlyChild?: boolean;
   name?: string;
   tag?: string;
@@ -156,6 +156,15 @@ function buildTree(
           : document.createElement(tagName);
       }
       if (el instanceof Element) {
+        if (!domParentTree) {
+          // some html elements may have side effects when setting their attributes.
+          // For example, setting the src attribute of an <img/> will trigger a
+          // request to get the corresponding image. This is something that we
+          // don't want at compile time. We avoid that by putting the content of
+          // the block in a <template/> element
+          const fragment = document.createElement("template").content;
+          fragment.appendChild(el);
+        }
         for (let i = 0; i < attrs.length; i++) {
           const attrName = attrs[i].name;
           const attrValue = attrs[i].value;
@@ -174,6 +183,14 @@ function buildTree(
               name: attrValue,
               tag: tagName,
             });
+          } else if (attrName.startsWith("block-property-")) {
+            const idx = parseInt(attrName.slice(15), 10);
+            info.push({
+              type: "property",
+              idx,
+              name: attrValue,
+              tag: tagName,
+            });
           } else if (attrName === "block-attributes") {
             info.push({
               type: "attributes",
@@ -245,7 +262,7 @@ function buildTree(
       };
     }
   }
-  throw new Error("boom");
+  throw new OwlError("boom");
 }
 
 function addRef(tree: IntermediateTree) {
@@ -367,15 +384,22 @@ function updateCtx(ctx: BlockCtx, tree: IntermediateTree) {
           };
         }
         break;
+      case "property": {
+        const refIdx = info.refIdx!;
+        const setProp = makePropSetter(info.name!);
+        ctx.locations.push({
+          idx: info.idx,
+          refIdx,
+          setData: setProp,
+          updateData: setProp,
+        });
+        break;
+      }
       case "attribute": {
         const refIdx = info.refIdx!;
         let updater: any;
         let setter: any;
-        if (isProp(info.tag!, info.name!)) {
-          const setProp = makePropSetter(info.name!);
-          setter = setProp;
-          updater = setProp;
-        } else if (info.name === "class") {
+        if (info.name === "class") {
           setter = setClass;
           updater = updateClass;
         } else {
@@ -507,9 +531,13 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
       return this.el!;
     }
 
-    moveBefore(other: Block | null, afterNode: Node | null) {
-      const target = other ? other.el! : afterNode;
-      nodeInsertBefore.call(this.parentEl, this.el!, target);
+    moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+      this.parentEl = parent;
+      nodeInsertBefore.call(parent, this.el!, node);
+    }
+
+    moveBeforeVNode(other: Block | null, afterNode: Node | null) {
+      nodeInsertBefore.call(this.parentEl, this.el!, other ? other.el! : afterNode);
     }
 
     toString() {

src/runtime/blockdom/event_catcher.ts

@@ -0,0 +1,111 @@
+import { createEventHandler } from "./events";
+import type { VNode } from "./index";
+
+type EventsSpec = { [name: string]: number };
+
+type Catcher = (child: VNode, handlers: any[]) => VNode;
+
+export function createCatcher(eventsSpec: EventsSpec): Catcher {
+  const n = Object.keys(eventsSpec).length;
+
+  class VCatcher {
+    child: VNode;
+    handlerData: any[];
+    handlerFns: any[] = [];
+
+    parentEl?: HTMLElement | undefined;
+    afterNode: Text | null = null;
+
+    constructor(child: VNode, handlers: any[]) {
+      this.child = child;
+      this.handlerData = handlers;
+    }
+
+    mount(parent: HTMLElement, afterNode: Node | null) {
+      this.parentEl = parent;
+      this.child.mount(parent, afterNode);
+      this.afterNode = document.createTextNode("");
+      parent.insertBefore(this.afterNode, afterNode);
+      this.wrapHandlerData();
+      for (let name in eventsSpec) {
+        const index = eventsSpec[name];
+        const handler = createEventHandler(name);
+        this.handlerFns[index] = handler;
+        handler.setup.call(parent, this.handlerData[index]);
+      }
+    }
+
+    wrapHandlerData() {
+      for (let i = 0; i < n; i++) {
+        let handler = this.handlerData[i];
+        // handler = [...mods, fn, comp], so we need to replace second to last elem
+        let idx = handler.length - 2;
+        let origFn = handler[idx];
+        const self = this;
+        handler[idx] = function (ev: any) {
+          const target = ev.target;
+          let currentNode: any = self.child.firstNode();
+          const afterNode = self.afterNode;
+          while (currentNode && currentNode !== afterNode) {
+            if (currentNode.contains(target)) {
+              return origFn.call(this, ev);
+            }
+            currentNode = currentNode.nextSibling;
+          }
+        };
+      }
+    }
+
+    moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+      this.parentEl = parent;
+      this.child.moveBeforeDOMNode(node, parent);
+      parent!.insertBefore(this.afterNode!, node);
+    }
+
+    moveBeforeVNode(other: VCatcher | null, afterNode: Node | null) {
+      if (other) {
+        // check this with @ged-odoo for use in foreach
+        afterNode = other.firstNode() || afterNode;
+      }
+      this.child.moveBeforeVNode(other ? other.child : null, afterNode);
+      this.parentEl!.insertBefore(this.afterNode!, afterNode);
+    }
+
+    patch(other: VCatcher, withBeforeRemove: boolean) {
+      if (this === other) {
+        return;
+      }
+      this.handlerData = other.handlerData;
+      this.wrapHandlerData();
+      for (let i = 0; i < n; i++) {
+        this.handlerFns[i].update.call(this.parentEl!, this.handlerData[i]);
+      }
+
+      this.child.patch(other.child, withBeforeRemove);
+    }
+
+    beforeRemove() {
+      this.child.beforeRemove();
+    }
+
+    remove() {
+      for (let i = 0; i < n; i++) {
+        this.handlerFns[i].remove.call(this.parentEl!);
+      }
+      this.child.remove();
+      this.afterNode!.remove();
+    }
+
+    firstNode(): Node | undefined {
+      return this.child.firstNode();
+    }
+
+    toString(): string {
+      return this.child.toString();
+    }
+  }
+
+  return function (child: VNode, handlers: any[]): VNode<VCatcher> {
+    return new VCatcher(child, handlers);
+  };
+}

src/runtime/blockdom/events.ts

@@ -27,8 +27,8 @@ function createElementHandler(evName: string, capture: boolean = false): EventHa
   }
 
   function listener(ev: Event) {
-    const currentTarget = ev.currentTarget;
-    if (!currentTarget || !document.contains(currentTarget as HTMLElement)) return;
+    const currentTarget = ev.currentTarget as HTMLElement;
+    if (!currentTarget || !currentTarget.ownerDocument.contains(currentTarget)) return;
     const data = (currentTarget as any)[eventKey];
     if (!data) return;
     config.mainEventHandler(data, ev, currentTarget);

src/runtime/blockdom/html.ts

@@ -29,14 +29,18 @@ class VHtml {
     }
   }
 
-  moveBefore(other: VHtml | null, afterNode: Node | null) {
-    const target = other ? other.content[0] : afterNode;
-    const parent = this.parentEl;
+  moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+    this.parentEl = parent;
     for (let elem of this.content) {
-      nodeInsertBefore.call(parent, elem, target);
+      nodeInsertBefore.call(parent, elem, node);
     }
   }
 
+  moveBeforeVNode(other: VHtml | null, afterNode: Node | null) {
+    const target = other ? other.content[0] : afterNode;
+    this.moveBeforeDOMNode(target);
+  }
+
   patch(other: VHtml) {
     if (this === other) {
       return;

src/runtime/blockdom/index.ts

@@ -10,7 +10,8 @@ export { createCatcher } from "./event_catcher";
 
 export interface VNode<T = any> {
   mount(parent: HTMLElement, afterNode: Node | null): void;
-  moveBefore(other: T | null, afterNode: Node | null): void;
+  moveBeforeDOMNode(node: Node | null, parent?: HTMLElement): void;
+  moveBeforeVNode(other: T | null, afterNode: Node | null): void;
   patch(other: T, withBeforeRemove: boolean): void;
   beforeRemove(): void;
   remove(): void;

src/runtime/blockdom/list.ts

@@ -38,14 +38,23 @@ class VList {
     this.parentEl = parent;
   }
 
-  moveBefore(other: VList | null, afterNode: Node | null) {
+  moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+    this.parentEl = parent;
+    const children = this.children;
+    for (let i = 0, l = children.length; i < l; i++) {
+      children[i].moveBeforeDOMNode(node, parent);
+    }
+    parent!.insertBefore(this.anchor!, node);
+  }
+
+  moveBeforeVNode(other: VList | null, afterNode: Node | null) {
     if (other) {
       const next = other!.children[0];
       afterNode = (next ? next.firstNode() : other!.anchor) || null;
     }
     const children = this.children;
     for (let i = 0, l = children.length; i < l; i++) {
-      children[i].moveBefore(null, afterNode);
+      children[i].moveBeforeVNode(null, afterNode);
     }
     this.parentEl!.insertBefore(this.anchor!, afterNode);
   }
@@ -66,7 +75,7 @@ class VList {
       patch: cPatch,
       remove: cRemove,
       beforeRemove,
-      moveBefore: cMoveBefore,
+      moveBeforeVNode: cMoveBefore,
       firstNode: cFirstNode,
     } = proto;
 

src/runtime/blockdom/multi.ts

@@ -38,7 +38,22 @@ export class VMulti {
     this.parentEl = parent;
   }
 
-  moveBefore(other: VMulti | null, afterNode: Node | null) {
+  moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+    this.parentEl = parent;
+    const children = this.children;
+    const anchors = this.anchors;
+    for (let i = 0, l = children.length; i < l; i++) {
+      let child = children[i];
+      if (child) {
+        child.moveBeforeDOMNode(node, parent);
+      } else {
+        const anchor = anchors![i];
+        nodeInsertBefore.call(parent, anchor, node);
+      }
+    }
+  }
+
+  moveBeforeVNode(other: VMulti | null, afterNode: Node | null) {
     if (other) {
       const next = other!.children[0];
       afterNode = (next ? next.firstNode() : other!.anchors![0]) || null;
@@ -49,7 +64,7 @@ export class VMulti {
     for (let i = 0, l = children.length; i < l; i++) {
       let child = children[i];
       if (child) {
-        child.moveBefore(null, afterNode);
+        child.moveBeforeVNode(null, afterNode);
       } else {
         const anchor = anchors![i];
         nodeInsertBefore.call(parent, anchor, afterNode);

src/runtime/blockdom/text.ts

@@ -23,9 +23,13 @@ abstract class VSimpleNode {
     this.el = node;
   }
 
-  moveBefore(other: VText | null, afterNode: Node | null) {
-    const target = other ? other.el! : afterNode;
-    nodeInsertBefore.call(this.parentEl, this.el!, target);
+  moveBeforeDOMNode(node: Node | null, parent = this.parentEl) {
+    this.parentEl = parent;
+    nodeInsertBefore.call(parent, this.el!, node);
+  }
+
+  moveBeforeVNode(other: VText | null, afterNode: Node | null) {
+    nodeInsertBefore.call(this.parentEl, this.el!, other ? other.el! : afterNode);
   }
 
   beforeRemove() {}

src/runtime/blockdom/toggler.ts

@@ -20,8 +20,12 @@ class VToggler {
     this.child.mount(parent, afterNode);
   }
 
-  moveBefore(other: VToggler | null, afterNode: Node | null) {
-    this.child.moveBefore(other ? other.child : null, afterNode);
+  moveBeforeDOMNode(node: Node | null, parent?: HTMLElement) {
+    this.child.moveBeforeDOMNode(node, parent);
+  }
+
+  moveBeforeVNode(other: VToggler | null, afterNode: Node | null) {
+    this.moveBeforeDOMNode((other && other.firstNode()) || afterNode);
   }
 
   patch(other: VToggler, withBeforeRemove: boolean) {

src/runtime/component.ts

@@ -1,15 +1,17 @@
+import { Schema } from "./validation";
 import type { ComponentNode } from "./component_node";
 
 // -----------------------------------------------------------------------------
 //  Component Class
 // -----------------------------------------------------------------------------
 
-type Props = { [key: string]: any };
+export type Props = { [key: string]: any };
 
 interface StaticComponentProperties {
   template: string;
   defaultProps?: any;
-  props?: any;
+  props?: Schema;
+  components?: { [componentName: string]: ComponentConstructor };
 }
 
 export type ComponentConstructor<P extends Props = any, E = any> = (new (
@@ -37,6 +39,6 @@ export class Component<Props = any, Env = any> {
   setup() {}
 
   render(deep: boolean = false) {
-    this.__owl__.render(deep);
+    this.__owl__.render(deep === true);
   }
 }

src/runtime/component_node.ts

@@ -1,32 +1,17 @@
-import type { App, Env } from "../app/app";
-import { BDom, VNode } from "../blockdom";
-import {
-  clearReactivesForCallback,
-  Reactive,
-  reactive,
-  TARGET,
-  NonReactive,
-  getSubscriptions,
-} from "../reactivity";
-import { batched, Callback } from "../utils";
-import { Component, ComponentConstructor } from "./component";
-import { fibersInError, handleError } from "./error_handling";
-import {
-  Fiber,
-  makeChildFiber,
-  makeRootFiber,
-  MountFiber,
-  MountOptions,
-  RootFiber,
-} from "./fibers";
-import { applyDefaultProps } from "./props_validation";
+import type { App, Env } from "./app";
+import { BDom, VNode } from "./blockdom";
+import { Component, ComponentConstructor, Props } from "./component";
+import { fibersInError, OwlError } from "./error_handling";
+import { Fiber, makeChildFiber, makeRootFiber, MountFiber, MountOptions } from "./fibers";
+import { clearReactivesForCallback, getSubscriptions, reactive, targets } from "./reactivity";
 import { STATUS } from "./status";
+import { batched, Callback } from "./utils";
 
 let currentNode: ComponentNode | null = null;
 
 export function getCurrent(): ComponentNode {
   if (!currentNode) {
-    throw new Error("No active component (a hook function should only be called in 'setup')");
+    throw new OwlError("No active component (a hook function should only be called in 'setup')");
   }
   return currentNode;
 }
@@ -35,6 +20,16 @@ export function useComponent(): Component {
   return currentNode!.component;
 }
 
+/**
+ * Apply default props (only top level).
+ */
+function applyDefaultProps<P extends object>(props: P, defaultProps: Partial<P>) {
+  for (let propName in defaultProps) {
+    if (props[propName] === undefined) {
+      (props as any)[propName] = defaultProps[propName];
+    }
+  }
+}
 // -----------------------------------------------------------------------------
 // Integration with reactivity system (useState)
 // -----------------------------------------------------------------------------
@@ -50,11 +45,11 @@ const batchedRenderFunctions = new WeakMap<ComponentNode, Callback>();
  *  relevant changes
  * @see reactive
  */
-export function useState<T extends object>(state: T): Reactive<T> | NonReactive<T> {
+export function useState<T extends object>(state: T): T {
   const node = getCurrent();
   let render = batchedRenderFunctions.get(node)!;
   if (!render) {
-    render = batched(node.render.bind(node));
+    render = batched(node.render.bind(node, false));
     batchedRenderFunctions.set(node, render);
     // manual implementation of onWillDestroy to break cyclic dependency
     node.willDestroy.push(clearReactivesForCallback.bind(null, render));
@@ -62,80 +57,13 @@ export function useState<T extends object>(state: T): Reactive<T> | NonReactive<
   return reactive(state, render);
 }
 
-// -----------------------------------------------------------------------------
-// component function (used in compiled template code)
-// -----------------------------------------------------------------------------
-type Props = { [key: string]: any };
-
-function arePropsDifferent(props1: Props, props2: Props): boolean {
-  for (let k in props1) {
-    if (props1[k] !== props2[k]) {
-      return true;
-    }
-  }
-  return Object.keys(props1).length !== Object.keys(props2).length;
-}
-
-export function component<P extends object>(
-  name: string | ComponentConstructor<P>,
-  props: P,
-  key: string,
-  ctx: ComponentNode,
-  parent: any
-): ComponentNode<P> {
-  let node: any = ctx.children[key];
-  let isDynamic = typeof name !== "string";
-
-  if (node) {
-    if (node.status < STATUS.MOUNTED) {
-      node.destroy();
-      node = undefined;
-    } else if (node.status === STATUS.DESTROYED) {
-      node = undefined;
-    }
-  }
-  if (isDynamic && node && node.component.constructor !== name) {
-    node = undefined;
-  }
-
-  const parentFiber = ctx.fiber!;
-  if (node) {
-    let shouldRender = node.forceNextRender;
-    if (shouldRender) {
-      node.forceNextRender = false;
-    } else {
-      const currentProps = node.component.props[TARGET];
-      shouldRender = parentFiber.deep || arePropsDifferent(currentProps, props);
-    }
-    if (shouldRender) {
-      node.updateAndRender(props, parentFiber);
-    }
-  } else {
-    // new component
-    let C;
-    if (isDynamic) {
-      C = name;
-    } else {
-      C = parent.constructor.components[name as any];
-      if (!C) {
-        throw new Error(`Cannot find the definition of component "${name}"`);
-      }
-    }
-    node = new ComponentNode(C, props, ctx.app, ctx);
-    ctx.children[key] = node;
-
-    node.initiateRender(new Fiber(node, parentFiber));
-  }
-  return node;
-}
-
 // -----------------------------------------------------------------------------
 //  Component VNode class
 // -----------------------------------------------------------------------------
 
 type LifecycleHook = Function;
 
-export class ComponentNode<P extends object = any, E = any> implements VNode<ComponentNode<P, E>> {
+export class ComponentNode<P extends Props = any, E = any> implements VNode<ComponentNode<P, E>> {
   el?: HTMLElement | Text | undefined;
   app: App;
   fiber: Fiber | null = null;
@@ -143,10 +71,11 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
   bdom: BDom | null = null;
   status: STATUS = STATUS.NEW;
   forceNextRender: boolean = false;
+  parentKey: string | null;
+  props: P;
 
   renderFn: Function;
   parent: ComponentNode | null;
-  level: number;
   childEnv: Env;
   children: { [key: string]: ComponentNode } = Object.create(null);
   refs: any = {};
@@ -159,17 +88,34 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
   patched: LifecycleHook[] = [];
   willDestroy: LifecycleHook[] = [];
 
-  constructor(C: ComponentConstructor<P, E>, props: P, app: App, parent?: ComponentNode) {
+  constructor(
+    C: ComponentConstructor<P, E>,
+    props: P,
+    app: App,
+    parent: ComponentNode | null,
+    parentKey: string | null
+  ) {
     currentNode = this;
     this.app = app;
-    this.parent = parent || null;
-    this.level = parent ? parent.level + 1 : 0;
-    applyDefaultProps(props, C);
+    this.parent = parent;
+    this.props = props;
+    this.parentKey = parentKey;
+    const defaultProps = C.defaultProps;
+    props = Object.assign({}, props);
+    if (defaultProps) {
+      applyDefaultProps(props, defaultProps);
+    }
     const env = (parent && parent.childEnv) || app.env;
     this.childEnv = env;
-    props = useState(props);
-    this.component = new C(props, env, this) as any;
-    this.renderFn = app.getTemplate(C.template).bind(this.component, this.component, this);
+    for (const key in props) {
+      const prop = props[key];
+      if (prop && typeof prop === "object" && targets.has(prop)) {
+        props[key] = useState(prop);
+      }
+    }
+    this.component = new C(props, env, this);
+    const ctx = Object.assign(Object.create(this.component), { this: this.component });
+    this.renderFn = app.getTemplate(C.template).bind(this.component, ctx, this);
     this.component.setup();
     currentNode = null;
   }
@@ -189,17 +135,17 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     try {
       await Promise.all(this.willStart.map((f) => f.call(component)));
     } catch (e) {
-      handleError({ node: this, error: e });
+      this.app.handleError({ node: this, error: e });
       return;
     }
     if (this.status === STATUS.NEW && this.fiber === fiber) {
-      this._render(fiber);
+      fiber.render();
     }
   }
 
-  async render(deep: boolean = false) {
+  async render(deep: boolean) {
     let current = this.fiber;
-    if (current && current.root!.locked) {
+    if (current && (current.root!.locked || (current as any).bdom === true)) {
       await Promise.resolve();
       // situation may have changed after the microtask tick
       current = this.fiber;
@@ -221,6 +167,7 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     const fiber = makeRootFiber(this);
     fiber.deep = deep;
     this.fiber = fiber;
+
     this.app.scheduler.addFiber(fiber);
     await Promise.resolve();
     if (this.status === STATUS.DESTROYED) {
@@ -238,16 +185,7 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     //   embedded in a rendering coming from above, so the fiber will be rendered
     //   in the next microtick anyway, so we should not render it again.
     if (this.fiber === fiber && (current || !fiber.parent)) {
-      this._render(fiber);
-    }
-  }
-
-  _render(fiber: Fiber | RootFiber) {
-    try {
-      fiber.bdom = this.renderFn();
-      fiber.root!.counter--;
-    } catch (e) {
-      handleError({ node: this, error: e });
+      fiber.render();
     }
   }
 
@@ -269,21 +207,37 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     for (let child of Object.values(this.children)) {
       child._destroy();
     }
-    for (let cb of this.willDestroy) {
-      cb.call(component);
+    if (this.willDestroy.length) {
+      try {
+        for (let cb of this.willDestroy) {
+          cb.call(component);
+        }
+      } catch (e) {
+        this.app.handleError({ error: e, node: this });
+      }
     }
     this.status = STATUS.DESTROYED;
   }
 
-  async updateAndRender(props: any, parentFiber: Fiber) {
+  async updateAndRender(props: P, parentFiber: Fiber) {
+    const rawProps = props;
+    props = Object.assign({}, props);
     // update
     const fiber = makeChildFiber(this, parentFiber);
     this.fiber = fiber;
     const component = this.component;
-    applyDefaultProps(props, component.constructor as any);
+    const defaultProps = (component.constructor as any).defaultProps;
+    if (defaultProps) {
+      applyDefaultProps(props, defaultProps);
+    }
 
     currentNode = this;
-    props = useState(props);
+    for (const key in props) {
+      const prop = props[key];
+      if (prop && typeof prop === "object" && targets.has(prop)) {
+        props[key] = useState(prop);
+      }
+    }
     currentNode = null;
     const prom = Promise.all(this.willUpdateProps.map((f) => f.call(component, props)));
     await prom;
@@ -291,7 +245,8 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
       return;
     }
     component.props = props;
-    this._render(fiber);
+    this.props = rawProps;
+    fiber.render();
     const parentRoot = parentFiber.root!;
     if (this.willPatch.length) {
       parentRoot.willPatch.push(fiber);
@@ -326,6 +281,19 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     }
   }
 
+  /**
+   * Sets a ref to a given HTMLElement.
+   *
+   * @param name the name of the ref to set
+   * @param el the HTMLElement to set the ref to. The ref is not set if the el
+   *  is null, but useRef will not return elements that are not in the DOM
+   */
+  setRef(name: string, el: HTMLElement | null) {
+    if (el) {
+      this.refs[name] = el;
+    }
+  }
+
   // ---------------------------------------------------------------------------
   // Block DOM methods
   // ---------------------------------------------------------------------------
@@ -341,11 +309,16 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     bdom.mount(parent, anchor);
     this.status = STATUS.MOUNTED;
     this.fiber!.appliedToDom = true;
+    this.children = this.fiber!.childrenMap;
     this.fiber = null;
   }
 
-  moveBefore(other: ComponentNode | null, afterNode: Node | null) {
-    this.bdom!.moveBefore(other ? other.bdom : null, afterNode);
+  moveBeforeDOMNode(node: Node | null, parent?: HTMLElement): void {
+    this.bdom!.moveBeforeDOMNode(node, parent);
+  }
+
+  moveBeforeVNode(other: ComponentNode<P, E> | null, afterNode: Node | null) {
+    this.bdom!.moveBeforeVNode(other ? other.bdom : null, afterNode);
   }
 
   patch() {
@@ -357,12 +330,16 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     }
   }
   _patch() {
-    const hasChildren = Object.keys(this.children).length > 0;
-    this.bdom!.patch(this!.fiber!.bdom!, hasChildren);
-    if (hasChildren) {
-      this.cleanOutdatedChildren();
+    let hasChildren = false;
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    for (let _k in this.children) {
+      hasChildren = true;
+      break;
     }
-    this.fiber!.appliedToDom = true;
+    const fiber = this.fiber!;
+    this.children = fiber.childrenMap;
+    this.bdom!.patch(fiber.bdom!, hasChildren);
+    fiber.appliedToDom = true;
     this.fiber = null;
   }
 
@@ -374,20 +351,6 @@ export class ComponentNode<P extends object = any, E = any> implements VNode<Com
     this.bdom!.remove();
   }
 
-  cleanOutdatedChildren() {
-    const children = this.children;
-    for (const key in children) {
-      const node = children[key];
-      const status = node.status;
-      if (status !== STATUS.MOUNTED) {
-        delete children[key];
-        if (status !== STATUS.DESTROYED) {
-          node.destroy();
-        }
-      }
-    }
-  }
-
   // ---------------------------------------------------------------------------
   // Some debug helpers
   // ---------------------------------------------------------------------------

src/runtime/error_handling.ts

@@ -1,11 +1,16 @@
 import type { ComponentNode } from "./component_node";
 import type { Fiber } from "./fibers";
 
+// Custom error class that wraps error that happen in the owl lifecycle
+export class OwlError extends Error {
+  cause?: any;
+}
+
 // Maps fibers to thrown errors
 export const fibersInError: WeakMap<Fiber, any> = new WeakMap();
 export const nodeErrorHandlers: WeakMap<ComponentNode, ((error: any) => void)[]> = new WeakMap();
 
-function _handleError(node: ComponentNode | null, error: any, isFirstRound = false): boolean {
+function _handleError(node: ComponentNode | null, error: any): boolean {
   if (!node) {
     return false;
   }
@@ -16,22 +21,19 @@ function _handleError(node: ComponentNode | null, error: any, isFirstRound = fal
 
   const errorHandlers = nodeErrorHandlers.get(node);
   if (errorHandlers) {
-    let stopped = false;
+    let handled = false;
     // execute in the opposite order
     for (let i = errorHandlers.length - 1; i >= 0; i--) {
       try {
         errorHandlers[i](error);
-        stopped = true;
+        handled = true;
         break;
       } catch (e) {
         error = e;
       }
     }
 
-    if (stopped) {
-      if (isFirstRound && fiber && fiber.node.fiber) {
-        fiber.root!.counter--;
-      }
+    if (handled) {
       return true;
     }
   }
@@ -40,7 +42,14 @@ function _handleError(node: ComponentNode | null, error: any, isFirstRound = fal
 
 type ErrorParams = { error: any } & ({ node: ComponentNode } | { fiber: Fiber });
 export function handleError(params: ErrorParams) {
-  const error = params.error;
+  let { error } = params;
+  // Wrap error if it wasn't wrapped by wrapError (ie when not in dev mode)
+  if (!(error instanceof OwlError)) {
+    error = Object.assign(
+      new OwlError(`An error occured in the owl lifecycle (see this Error's "cause" property)`),
+      { cause: error }
+    );
+  }
   const node = "node" in params ? params.node : params.fiber.node;
   const fiber = "fiber" in params ? params.fiber : node.fiber!;
 
@@ -54,7 +63,7 @@ export function handleError(params: ErrorParams) {
 
   fibersInError.set(fiber.root!, error);
 
-  const handled = _handleError(node, error, true);
+  const handled = _handleError(node, error);
   if (!handled) {
     console.warn(`[Owl] Unhandled error. Destroying the root component`);
     try {
@@ -62,5 +71,6 @@ export function handleError(params: ErrorParams) {
     } catch (e) {
       console.error(e);
     }
+    throw error;
   }
 }

src/runtime/event_handling.ts

@@ -1,5 +1,6 @@
-import { filterOutModifiersFromData } from "../blockdom/config";
+import { filterOutModifiersFromData } from "./blockdom/config";
 import { STATUS } from "./status";
+import { OwlError } from "./error_handling";
 
 export const mainEventHandler = (data: any, ev: Event, currentTarget?: EventTarget | null) => {
   const { data: _data, modifiers } = filterOutModifiersFromData(data);
@@ -33,7 +34,7 @@ export const mainEventHandler = (data: any, ev: Event, currentTarget?: EventTarg
   if (Object.hasOwnProperty.call(data, 0)) {
     const handler = data[0];
     if (typeof handler !== "function") {
-      throw new Error(`Invalid handler (expected a function, received: '${handler}')`);
+      throw new OwlError(`Invalid handler (expected a function, received: '${handler}')`);
     }
     let node = data[1] ? data[1].__owl__ : null;
     if (node ? node.status === STATUS.MOUNTED : true) {

src/runtime/fibers.ts

@@ -1,6 +1,6 @@
-import { BDom, mount } from "../blockdom";
+import { BDom, mount } from "./blockdom";
 import type { ComponentNode } from "./component_node";
-import { fibersInError, handleError } from "./error_handling";
+import { fibersInError, OwlError } from "./error_handling";
 import { STATUS } from "./status";
 
 export function makeChildFiber(node: ComponentNode, parent: Fiber): Fiber {
@@ -16,8 +16,14 @@ export function makeRootFiber(node: ComponentNode): Fiber {
   let current = node.fiber;
   if (current) {
     let root = current.root!;
-    root.counter = root.counter + 1 - cancelFibers(current.children);
+    // lock root fiber because canceling children fibers may destroy components,
+    // which means any arbitrary code can be run in onWillDestroy, which may
+    // trigger new renderings
+    root.locked = true;
+    root.setCounter(root.counter + 1 - cancelFibers(current.children));
+    root.locked = false;
     current.children = [];
+    current.childrenMap = {};
     current.bdom = null;
     if (fibersInError.has(current)) {
       fibersInError.delete(current);
@@ -36,13 +42,23 @@ export function makeRootFiber(node: ComponentNode): Fiber {
   return fiber;
 }
 
+function throwOnRender() {
+  throw new OwlError("Attempted to render cancelled fiber");
+}
+
 /**
  * @returns number of not-yet rendered fibers cancelled
  */
 function cancelFibers(fibers: Fiber[]): number {
   let result = 0;
   for (let fiber of fibers) {
-    fiber.node.fiber = null;
+    let node = fiber.node;
+    fiber.render = throwOnRender;
+    if (node.status === STATUS.NEW) {
+      node.destroy();
+      delete node.parent!.children[node.parentKey!];
+    }
+    node.fiber = null;
     if (fiber.bdom) {
       // if fiber has been rendered, this means that the component props have
       // been updated. however, this fiber will not be patched to the dom, so
@@ -50,7 +66,7 @@ function cancelFibers(fibers: Fiber[]): number {
       // the same props, and skip the render completely. With the next line,
       // we kindly request the component code to force a render, so it works as
       // expected.
-      fiber.node.forceNextRender = true;
+      node.forceNextRender = true;
     } else {
       result++;
     }
@@ -67,6 +83,7 @@ export class Fiber {
   children: Fiber[] = [];
   appliedToDom = false;
   deep: boolean = false;
+  childrenMap: ComponentNode["children"] = {};
 
   constructor(node: ComponentNode, parent: Fiber | null) {
     this.node = node;
@@ -74,13 +91,50 @@ export class Fiber {
     if (parent) {
       this.deep = parent.deep;
       const root = parent.root!;
-      root.counter++;
+      root.setCounter(root.counter + 1);
       this.root = root;
       parent.children.push(this);
     } else {
       this.root = this as any;
     }
   }
+
+  render() {
+    // if some parent has a fiber => register in followup
+    let prev = this.root!.node;
+    let scheduler = prev.app.scheduler;
+    let current = prev.parent;
+    while (current) {
+      if (current.fiber) {
+        let root = current.fiber.root!;
+        if (root.counter === 0 && prev.parentKey! in current.fiber.childrenMap) {
+          current = root.node;
+        } else {
+          scheduler.delayedRenders.push(this);
+          return;
+        }
+      }
+      prev = current;
+      current = current.parent;
+    }
+
+    // there are no current rendering from above => we can render
+    this._render();
+  }
+
+  _render() {
+    const node = this.node;
+    const root = this.root;
+    if (root) {
+      try {
+        (this.bdom as any) = true;
+        this.bdom = node.renderFn();
+      } catch (e) {
+        node.app.handleError({ node, error: e });
+      }
+      root.setCounter(root.counter - 1);
+    }
+  }
 }
 
 export class RootFiber extends Fiber {
@@ -141,7 +195,14 @@ export class RootFiber extends Fiber {
       }
     } catch (e) {
       this.locked = false;
-      handleError({ fiber: current || this, error: e });
+      node.app.handleError({ fiber: current || this, error: e });
+    }
+  }
+
+  setCounter(newValue: number) {
+    this.counter = newValue;
+    if (newValue === 0) {
+      this.node.app.scheduler.flush();
     }
   }
 }
@@ -165,6 +226,7 @@ export class MountFiber extends RootFiber {
     let current: Fiber | undefined = this;
     try {
       const node = this.node;
+      node.children = this.childrenMap;
       (node.app.constructor as any).validateTarget(this.target);
       if (node.bdom) {
         // this is a complicated situation: if we mount a fiber with an existing
@@ -197,7 +259,7 @@ export class MountFiber extends RootFiber {
         }
       }
     } catch (e) {
-      handleError({ fiber: current as Fiber, error: e });
+      this.node.app.handleError({ fiber: current as Fiber, error: e });
     }
   }
 }

src/runtime/hooks.ts

@@ -1,6 +1,6 @@
-import type { Env } from "./app/app";
-import { getCurrent } from "./component/component_node";
-import { onMounted, onPatched, onWillUnmount } from "./component/lifecycle_hooks";
+import type { Env } from "./app";
+import { getCurrent } from "./component_node";
+import { onMounted, onPatched, onWillUnmount } from "./lifecycle_hooks";
 
 // -----------------------------------------------------------------------------
 // useRef
@@ -15,7 +15,8 @@ export function useRef<T extends HTMLElement = HTMLElement>(name: string): { el:
   const refs = node.refs;
   return {
     get el(): T | null {
-      return refs[name] || null;
+      const el = refs[name];
+      return el?.ownerDocument.contains(el) ? el : null;
     },
   };
 }
@@ -117,7 +118,7 @@ export function useEffect(effect: Effect, computeDependencies: () => any[] = ()
  *  `useExternalListener(window, 'click', this._doSomething);`
  * */
 export function useExternalListener(
-  target: HTMLElement | typeof window,
+  target: EventTarget,
   eventName: string,
   handler: EventListener,
   eventParams?: AddEventListenerOptions

src/runtime/index.ts

@@ -0,0 +1,62 @@
+import { App } from "./app";
+import {
+  config,
+  createBlock,
+  html,
+  list,
+  mount as blockMount,
+  multi,
+  patch,
+  remove,
+  text,
+  toggler,
+  comment,
+} from "./blockdom";
+import { mainEventHandler } from "./event_handling";
+
+config.shouldNormalizeDom = false;
+config.mainEventHandler = mainEventHandler;
+
+export const blockDom = {
+  config,
+  // bdom entry points
+  mount: blockMount,
+  patch,
+  remove,
+  // bdom block types
+  list,
+  multi,
+  text,
+  toggler,
+  createBlock,
+  html,
+  comment,
+};
+
+export { App, mount } from "./app";
+export { xml } from "./template_set";
+export { Component } from "./component";
+export type { ComponentConstructor } from "./component";
+export { useComponent, useState } from "./component_node";
+export { status } from "./status";
+export { reactive, markRaw, toRaw } from "./reactivity";
+export { useEffect, useEnv, useExternalListener, useRef, useChildSubEnv, useSubEnv } from "./hooks";
+export { EventBus, whenReady, loadFile, markup } from "./utils";
+export {
+  onWillStart,
+  onMounted,
+  onWillUnmount,
+  onWillUpdateProps,
+  onWillPatch,
+  onPatched,
+  onWillRender,
+  onRendered,
+  onWillDestroy,
+  onError,
+} from "./lifecycle_hooks";
+export { validate } from "./validation";
+export { OwlError } from "./error_handling";
+
+export const __info__ = {
+  version: App.version,
+};

src/runtime/lifecycle_hooks.ts

@@ -1,28 +1,42 @@
 import { getCurrent } from "./component_node";
-import { nodeErrorHandlers } from "./error_handling";
+import { nodeErrorHandlers, OwlError } from "./error_handling";
 
+const TIMEOUT = Symbol("timeout");
 function wrapError(fn: (...args: any[]) => any, hookName: string) {
-  const error = new Error(`The following error occurred in ${hookName}: `) as Error & {
+  const error = new OwlError(`The following error occurred in ${hookName}: `) as Error & {
     cause: any;
   };
+  const timeoutError = new OwlError(`${hookName}'s promise hasn't resolved after 3 seconds`);
+  const node = getCurrent();
   return (...args: any[]) => {
+    const onError = (cause: any) => {
+      error.cause = cause;
+      if (cause instanceof Error) {
+        error.message += `"${cause.message}"`;
+      } else {
+        error.message = `Something that is not an Error was thrown in ${hookName} (see this Error's "cause" property)`;
+      }
+      throw error;
+    };
     try {
       const result = fn(...args);
       if (result instanceof Promise) {
-        return result.catch((cause) => {
-          error.cause = cause;
-          if (cause instanceof Error) {
-            error.message += `"${cause.message}"`;
-          }
-          throw error;
-        });
+        if (hookName === "onWillStart" || hookName === "onWillUpdateProps") {
+          const fiber = node.fiber;
+          Promise.race([
+            result.catch(() => {}),
+            new Promise((resolve) => setTimeout(() => resolve(TIMEOUT), 3000)),
+          ]).then((res) => {
+            if (res === TIMEOUT && node.fiber === fiber) {
+              console.warn(timeoutError);
+            }
+          });
+        }
+        return result.catch(onError);
       }
       return result;
     } catch (cause) {
-      if (cause instanceof Error) {
-        error.message += `"${cause.message}"`;
-      }
-      throw error;
+      onError(cause);
     }
   };
 }
@@ -49,7 +63,7 @@ export function onMounted(fn: () => void | any) {
   node.mounted.push(decorate(fn.bind(node.component), "onMounted"));
 }
 
-export function onWillPatch(fn: () => Promise<void> | any | void) {
+export function onWillPatch(fn: () => any | void) {
   const node = getCurrent();
   const decorate = node.app.dev ? wrapError : (fn: any) => fn;
   node.willPatch.unshift(decorate(fn.bind(node.component), "onWillPatch"));
@@ -61,13 +75,13 @@ export function onPatched(fn: () => void | any) {
   node.patched.push(decorate(fn.bind(node.component), "onPatched"));
 }
 
-export function onWillUnmount(fn: () => Promise<void> | void | any) {
+export function onWillUnmount(fn: () => void | any) {
   const node = getCurrent();
   const decorate = node.app.dev ? wrapError : (fn: any) => fn;
   node.willUnmount.unshift(decorate(fn.bind(node.component), "onWillUnmount"));
 }
 
-export function onWillDestroy(fn: () => Promise<void> | void | any) {
+export function onWillDestroy(fn: () => void | any) {
   const node = getCurrent();
   const decorate = node.app.dev ? wrapError : (fn: any) => fn;
   node.willDestroy.push(decorate(fn.bind(node.component), "onWillDestroy"));

src/runtime/portal.ts

@@ -0,0 +1,90 @@
+import { onMounted, onWillUnmount } from "./lifecycle_hooks";
+import { BDom, text, VNode } from "./blockdom";
+import { Component } from "./component";
+import { OwlError } from "./error_handling";
+
+const VText: any = text("").constructor;
+
+class VPortal extends VText implements Partial<VNode<VPortal>> {
+  content: BDom | null;
+  selector: string;
+  target: HTMLElement | null = null;
+
+  constructor(selector: string, content: BDom) {
+    super("");
+    this.selector = selector;
+    this.content = content;
+  }
+
+  mount(parent: HTMLElement, anchor: ChildNode) {
+    super.mount(parent, anchor);
+    this.target = document.querySelector(this.selector) as any;
+    if (this.target) {
+      this.content!.mount(this.target!, null);
+    } else {
+      this.content!.mount(parent, anchor);
+    }
+  }
+
+  beforeRemove() {
+    this.content!.beforeRemove();
+  }
+  remove() {
+    if (this.content) {
+      super.remove();
+      this.content!.remove();
+      this.content = null;
+    }
+  }
+
+  patch(other: VPortal) {
+    super.patch(other);
+    if (this.content) {
+      this.content.patch(other.content!, true);
+    } else {
+      this.content = other.content;
+      this.content!.mount(this.target!, null);
+    }
+  }
+}
+
+/**
+ * kind of similar to <t t-slot="default"/>, but it wraps it around a VPortal
+ */
+export function portalTemplate(app: any, bdom: any, helpers: any) {
+  let { callSlot } = helpers;
+  return function template(ctx: any, node: any, key = ""): any {
+    return new VPortal(ctx.props.target, callSlot(ctx, node, key, "default", false, null));
+  };
+}
+
+export class Portal extends Component {
+  static template = "__portal__";
+  static props = {
+    target: {
+      type: String,
+    },
+    slots: true,
+  };
+
+  setup() {
+    const node: any = this.__owl__;
+
+    onMounted(() => {
+      const portal: VPortal = node.bdom;
+      if (!portal.target) {
+        const target: HTMLElement = document.querySelector(this.props.target);
+        if (target) {
+          portal.content!.moveBeforeDOMNode(target.firstChild, target);
+        } else {
+          throw new OwlError("invalid portal target");
+        }
+      }
+    });
+
+    onWillUnmount(() => {
+      const portal: VPortal = node.bdom;
+      portal.remove();
+    });
+  }
+}

src/runtime/reactivity.ts

@@ -1,24 +1,22 @@
-import { Callback } from "./utils";
+import type { Callback } from "./utils";
+import { OwlError } from "./error_handling";
 
-// Allows to get the target of a Reactive (used for making a new Reactive from the underlying object)
-export const TARGET = Symbol("Target");
-// Escape hatch to prevent reactivity system to turn something into a reactive
-const SKIP = Symbol("Skip");
 // Special key to subscribe to, to be notified of key creation/deletion
 const KEYCHANGES = Symbol("Key changes");
+// Used to specify the absence of a callback, can be used as WeakMap key but
+// should only be used as a sentinel value and never called.
+const NO_CALLBACK = () => {
+  throw new Error("Called NO_CALLBACK. Owl is broken, please report this to the maintainers.");
+};
 
+// The following types only exist to signify places where objects are expected
+// to be reactive or not, they provide no type checking benefit over "object"
 type Target = object;
+type Reactive<T extends Target> = T;
+
 type Collection = Set<any> | Map<any, any> | WeakMap<any, any>;
 type CollectionRawType = "Set" | "Map" | "WeakMap";
 
-export type Reactive<T extends Target = Target> = T & {
-  [TARGET]: any;
-};
-
-export type NonReactive<T extends Target = Target> = T & {
-  [SKIP]: any;
-};
-
 const objectToString = Object.prototype.toString;
 const objectHasOwnProperty = Object.prototype.hasOwnProperty;
 
@@ -35,7 +33,7 @@ const COLLECTION_RAWTYPES = new Set(["Set", "Map", "WeakMap"]);
  * @returns the raw type of the object
  */
 function rawType(obj: any) {
-  return objectToString.call(obj).slice(8, -1);
+  return objectToString.call(toRaw(obj)).slice(8, -1);
 }
 /**
  * Checks whether a given value can be made into a reactive object.
@@ -60,15 +58,16 @@ function possiblyReactive(val: any, cb: Callback) {
   return canBeMadeReactive(val) ? reactive(val, cb) : val;
 }
 
+const skipped = new WeakSet<Target>();
 /**
  * Mark an object or array so that it is ignored by the reactivity system
  *
  * @param value the value to mark
  * @returns the object itself
  */
-export function markRaw<T extends Target>(value: T): NonReactive<T> {
-  (value as any)[SKIP] = true;
-  return value as NonReactive<T>;
+export function markRaw<T extends Target>(value: T): T {
+  skipped.add(value);
+  return value;
 }
 
 /**
@@ -77,8 +76,8 @@ export function markRaw<T extends Target>(value: T): NonReactive<T> {
  * @param value a reactive value
  * @returns the underlying value
  */
-export function toRaw<T extends object>(value: Reactive<T>): T {
-  return value[TARGET] || value;
+export function toRaw<T extends Target, U extends Reactive<T>>(value: U | T): T {
+  return targets.has(value) ? (targets.get(value) as T) : value;
 }
 
 const targetToKeysToCallbacks = new WeakMap<Target, Map<PropertyKey, Set<Callback>>>();
@@ -92,6 +91,9 @@ const targetToKeysToCallbacks = new WeakMap<Target, Map<PropertyKey, Set<Callbac
  * @param callback the function to call when the key changes
  */
 function observeTargetKey(target: Target, key: PropertyKey, callback: Callback): void {
+  if (callback === NO_CALLBACK) {
+    return;
+  }
   if (!targetToKeysToCallbacks.get(target)) {
     targetToKeysToCallbacks.set(target, new Map());
   }
@@ -146,8 +148,11 @@ export function clearReactivesForCallback(callback: Callback): void {
     if (!observedKeys) {
       continue;
     }
-    for (const callbacks of observedKeys.values()) {
+    for (const [key, callbacks] of observedKeys.entries()) {
       callbacks.delete(callback);
+      if (!callbacks.size) {
+        observedKeys.delete(key);
+      }
     }
   }
   targetsToClear.clear();
@@ -157,14 +162,20 @@ export function getSubscriptions(callback: Callback) {
   const targets = callbacksToTargets.get(callback) || [];
   return [...targets].map((target) => {
     const keysToCallbacks = targetToKeysToCallbacks.get(target);
-    return {
-      target,
-      keys: keysToCallbacks ? [...keysToCallbacks.keys()] : [],
-    };
+    let keys = [];
+    if (keysToCallbacks) {
+      for (const [key, cbs] of keysToCallbacks) {
+        if (cbs.has(callback)) {
+          keys.push(key);
+        }
+      }
+    }
+    return { target, keys };
   });
 }
-
-const reactiveCache = new WeakMap<Target, WeakMap<Callback, Reactive>>();
+// Maps reactive objects to the underlying target
+export const targets = new WeakMap<Reactive<Target>, Target>();
+const reactiveCache = new WeakMap<Target, WeakMap<Callback, Reactive<Target>>>();
 /**
  * Creates a reactive proxy for an object. Reading data on the reactive object
  * subscribes to changes to the data. Writing data on the object will cause the
@@ -179,7 +190,7 @@ const reactiveCache = new WeakMap<Target, WeakMap<Callback, Reactive>>();
  * Subscriptions:
  * + Reading a property on an object will subscribe you to changes in the value
  *    of that property.
- * + Accessing an object keys (eg with Object.keys or with `for..in`) will
+ * + Accessing an object's keys (eg with Object.keys or with `for..in`) will
  *    subscribe you to the creation/deletion of keys. Checking the presence of a
  *    key on the object with 'in' has the same effect.
  * - getOwnPropertyDescriptor does not currently subscribe you to the property.
@@ -192,22 +203,19 @@ const reactiveCache = new WeakMap<Target, WeakMap<Callback, Reactive>>();
  *  reactive has changed
  * @returns a proxy that tracks changes to it
  */
-export function reactive<T extends Target>(
-  target: T,
-  callback: Callback = () => {}
-): Reactive<T> | NonReactive<T> {
+export function reactive<T extends Target>(target: T, callback: Callback = NO_CALLBACK): T {
   if (!canBeMadeReactive(target)) {
-    throw new Error(`Cannot make the given value reactive`);
+    throw new OwlError(`Cannot make the given value reactive`);
   }
-  if (SKIP in target) {
-    return target as NonReactive<T>;
+  if (skipped.has(target)) {
+    return target;
   }
-  const originalTarget = (target as Reactive)[TARGET];
-  if (originalTarget) {
-    return reactive(originalTarget, callback);
+  if (targets.has(target)) {
+    // target is reactive, create a reactive on the underlying object instead
+    return reactive(targets.get(target) as T, callback);
   }
   if (!reactiveCache.has(target)) {
-    reactiveCache.set(target, new Map());
+    reactiveCache.set(target, new WeakMap());
   }
   const reactivesForTarget = reactiveCache.get(target)!;
   if (!reactivesForTarget.has(callback)) {
@@ -217,6 +225,7 @@ export function reactive<T extends Target>(
       : basicProxyHandler<T>(callback);
     const proxy = new Proxy(target, handler as ProxyHandler<T>) as Reactive<T>;
     reactivesForTarget.set(callback, proxy);
+    targets.set(proxy, target);
   }
   return reactivesForTarget.get(callback) as Reactive<T>;
 }
@@ -228,24 +237,29 @@ export function reactive<T extends Target>(
  */
 function basicProxyHandler<T extends Target>(callback: Callback): ProxyHandler<T> {
   return {
-    get(target: any, key: PropertyKey, proxy: Reactive<T>) {
-      if (key === TARGET) {
-        return target;
+    get(target, key, receiver) {
+      // non-writable non-configurable properties cannot be made reactive
+      const desc = Object.getOwnPropertyDescriptor(target, key);
+      if (desc && !desc.writable && !desc.configurable) {
+        return Reflect.get(target, key, receiver);
       }
       observeTargetKey(target, key, callback);
-      return possiblyReactive(Reflect.get(target, key, proxy), callback);
+      return possiblyReactive(Reflect.get(target, key, receiver), callback);
     },
-    set(target, key, value, proxy) {
-      const isNewKey = !objectHasOwnProperty.call(target, key);
-      const originalValue = Reflect.get(target, key, proxy);
-      const ret = Reflect.set(target, key, value, proxy);
-      if (isNewKey) {
+    set(target, key, value, receiver) {
+      const hadKey = objectHasOwnProperty.call(target, key);
+      const originalValue = Reflect.get(target, key, receiver);
+      const ret = Reflect.set(target, key, value, receiver);
+      if (!hadKey && objectHasOwnProperty.call(target, key)) {
         notifyReactives(target, KEYCHANGES);
       }
       // While Array length may trigger the set trap, it's not actually set by this
       // method but is updated behind the scenes, and the trap is not called with the
       // new value. We disable the "same-value-optimization" for it because of that.
-      if (originalValue !== value || (Array.isArray(target) && key === "length")) {
+      if (
+        originalValue !== Reflect.get(target, key, receiver) ||
+        (key === "length" && Array.isArray(target))
+      ) {
         notifyReactives(target, key);
       }
       return ret;
@@ -438,10 +452,8 @@ function collectionsProxyHandler<T extends Collection>(
   // property is read.
   const specialHandlers = rawTypeToFuncHandlers[targetRawType](target, callback);
   return Object.assign(basicProxyHandler(callback), {
+    // FIXME: probably broken when part of prototype chain since we ignore the receiver
     get(target: any, key: PropertyKey) {
-      if (key === TARGET) {
-        return target;
-      }
       if (objectHasOwnProperty.call(specialHandlers, key)) {
         return (specialHandlers as any)[key];
       }

src/runtime/scheduler.ts

@@ -0,0 +1,76 @@
+import { fibersInError } from "./error_handling";
+import { Fiber, RootFiber } from "./fibers";
+import { STATUS } from "./status";
+
+// -----------------------------------------------------------------------------
+//  Scheduler
+// -----------------------------------------------------------------------------
+
+export class Scheduler {
+  // capture the value of requestAnimationFrame as soon as possible, to avoid
+  // interactions with other code, such as test frameworks that override them
+  static requestAnimationFrame = window.requestAnimationFrame.bind(window);
+  tasks: Set<RootFiber> = new Set();
+  requestAnimationFrame: Window["requestAnimationFrame"];
+  frame: number = 0;
+  delayedRenders: Fiber[] = [];
+
+  constructor() {
+    this.requestAnimationFrame = Scheduler.requestAnimationFrame;
+  }
+
+  addFiber(fiber: Fiber) {
+    this.tasks.add(fiber.root!);
+  }
+
+  /**
+   * Process all current tasks. This only applies to the fibers that are ready.
+   * Other tasks are left unchanged.
+   */
+  flush() {
+    if (this.delayedRenders.length) {
+      let renders = this.delayedRenders;
+      this.delayedRenders = [];
+      for (let f of renders) {
+        if (f.root && f.node.status !== STATUS.DESTROYED && f.node.fiber === f) {
+          f.render();
+        }
+      }
+    }
+
+    if (this.frame === 0) {
+      this.frame = this.requestAnimationFrame(() => {
+        this.frame = 0;
+        this.tasks.forEach((fiber) => this.processFiber(fiber));
+        for (let task of this.tasks) {
+          if (task.node.status === STATUS.DESTROYED) {
+            this.tasks.delete(task);
+          }
+        }
+      });
+    }
+  }
+
+  processFiber(fiber: RootFiber) {
+    if (fiber.root !== fiber) {
+      this.tasks.delete(fiber);
+      return;
+    }
+    const hasError = fibersInError.has(fiber);
+    if (hasError && fiber.counter !== 0) {
+      this.tasks.delete(fiber);
+      return;
+    }
+    if (fiber.node.status === STATUS.DESTROYED) {
+      this.tasks.delete(fiber);
+      return;
+    }
+
+    if (fiber.counter === 0) {
+      if (!hasError) {
+        fiber.complete();
+      }
+      this.tasks.delete(fiber);
+    }
+  }
+}

src/runtime/template_helpers.ts

@@ -0,0 +1,249 @@
+import { BDom, multi, text, toggler, createCatcher } from "./blockdom";
+import { Markup } from "./utils";
+import { html } from "./blockdom/index";
+import { isOptional, validateSchema } from "./validation";
+import type { ComponentConstructor } from "./component";
+import { markRaw } from "./reactivity";
+import { OwlError } from "./error_handling";
+import type { ComponentNode } from "./component_node";
+
+const ObjectCreate = Object.create;
+/**
+ * This file contains utility functions that will be injected in each template,
+ * to perform various useful tasks in the compiled code.
+ */
+
+function withDefault(value: any, defaultValue: any): any {
+  return value === undefined || value === null || value === false ? defaultValue : value;
+}
+
+function callSlot(
+  ctx: any,
+  parent: any,
+  key: string,
+  name: string,
+  dynamic: boolean,
+  extra: any,
+  defaultContent?: (ctx: any, node: any, key: string) => BDom
+): BDom {
+  key = key + "__slot_" + name;
+  const slots = ctx.props.slots || {};
+  const { __render, __ctx, __scope } = slots[name] || {};
+  const slotScope = ObjectCreate(__ctx || {});
+  if (__scope) {
+    slotScope[__scope] = extra;
+  }
+  const slotBDom = __render ? __render(slotScope, parent, key) : null;
+  if (defaultContent) {
+    let child1: BDom | undefined = undefined;
+    let child2: BDom | undefined = undefined;
+    if (slotBDom) {
+      child1 = dynamic ? toggler(name, slotBDom) : slotBDom;
+    } else {
+      child2 = defaultContent(ctx, parent, key);
+    }
+    return multi([child1, child2]);
+  }
+  return slotBDom || text("");
+}
+
+function capture(ctx: any): any {
+  const result = ObjectCreate(ctx);
+  for (let k in ctx) {
+    result[k] = ctx[k];
+  }
+  return result;
+}
+
+function withKey(elem: any, k: string) {
+  elem.key = k;
+  return elem;
+}
+
+function prepareList(collection: any): [any[], any[], number, any[]] {
+  let keys: any[];
+  let values: any[];
+
+  if (Array.isArray(collection)) {
+    keys = collection;
+    values = collection;
+  } else if (collection) {
+    values = Object.keys(collection);
+    keys = Object.values(collection);
+  } else {
+    throw new OwlError("Invalid loop expression");
+  }
+  const n = values.length;
+  return [keys, values, n, new Array(n)];
+}
+
+const isBoundary = Symbol("isBoundary");
+
+function setContextValue(ctx: { [key: string]: any }, key: string, value: any): void {
+  const ctx0 = ctx;
+  while (!ctx.hasOwnProperty(key) && !ctx.hasOwnProperty(isBoundary)) {
+    const newCtx = ctx.__proto__;
+    if (!newCtx) {
+      ctx = ctx0;
+      break;
+    }
+    ctx = newCtx;
+  }
+  ctx[key] = value;
+}
+
+function toNumber(val: string): number | string {
+  const n = parseFloat(val);
+  return isNaN(n) ? val : n;
+}
+
+function shallowEqual(l1: any[], l2: any[]): boolean {
+  for (let i = 0, l = l1.length; i < l; i++) {
+    if (l1[i] !== l2[i]) {
+      return false;
+    }
+  }
+  return true;
+}
+
+class LazyValue {
+  fn: any;
+  ctx: any;
+  component: any;
+  node: any;
+  key: any;
+
+  constructor(fn: any, ctx: any, component: any, node: any, key: any) {
+    this.fn = fn;
+    this.ctx = capture(ctx);
+    this.component = component;
+    this.node = node;
+    this.key = key;
+  }
+
+  evaluate(): any {
+    return this.fn.call(this.component, this.ctx, this.node, this.key);
+  }
+
+  toString() {
+    return this.evaluate().toString();
+  }
+}
+
+/*
+ * Safely outputs `value` as a block depending on the nature of `value`
+ */
+export function safeOutput(value: any, defaultValue?: any): ReturnType<typeof toggler> {
+  if (value === undefined) {
+    return defaultValue ? toggler("default", defaultValue) : toggler("undefined", text(""));
+  }
+  let safeKey;
+  let block;
+  switch (typeof value) {
+    case "object":
+      if (value instanceof Markup) {
+        safeKey = `string_safe`;
+        block = html(value as string);
+      } else if (value instanceof LazyValue) {
+        safeKey = `lazy_value`;
+        block = value.evaluate();
+      } else if (value instanceof String) {
+        safeKey = "string_unsafe";
+        block = text(value);
+      } else {
+        // Assuming it is a block
+        safeKey = "block_safe";
+        block = value;
+      }
+      break;
+    case "string":
+      safeKey = "string_unsafe";
+      block = text(value);
+      break;
+    default:
+      safeKey = "string_unsafe";
+      block = text(String(value));
+  }
+  return toggler(safeKey, block);
+}
+
+/**
+ * Validate the component props (or next props) against the (static) props
+ * description.  This is potentially an expensive operation: it may needs to
+ * visit recursively the props and all the children to check if they are valid.
+ * This is why it is only done in 'dev' mode.
+ */
+export function validateProps<P>(name: string | ComponentConstructor<P>, props: P, comp?: any) {
+  const ComponentClass =
+    typeof name !== "string"
+      ? name
+      : (comp.constructor.components[name] as ComponentConstructor<P> | undefined);
+
+  if (!ComponentClass) {
+    // this is an error, wrong component. We silently return here instead so the
+    // error is triggered by the usual path ('component' function)
+    return;
+  }
+
+  const schema = ComponentClass.props;
+  if (!schema) {
+    if (comp.__owl__.app.warnIfNoStaticProps) {
+      console.warn(`Component '${ComponentClass.name}' does not have a static props description`);
+    }
+    return;
+  }
+  const defaultProps = ComponentClass.defaultProps;
+  if (defaultProps) {
+    let isMandatory = (name: string) =>
+      Array.isArray(schema)
+        ? schema.includes(name)
+        : name in schema && !("*" in schema) && !isOptional(schema[name]);
+    for (let p in defaultProps) {
+      if (isMandatory(p)) {
+        throw new OwlError(
+          `A default value cannot be defined for a mandatory prop (name: '${p}', component: ${ComponentClass.name})`
+        );
+      }
+    }
+  }
+
+  const errors = validateSchema(props, schema);
+  if (errors.length) {
+    throw new OwlError(
+      `Invalid props for component '${ComponentClass.name}': ` + errors.join(", ")
+    );
+  }
+}
+
+function makeRefWrapper(node: ComponentNode) {
+  let refNames: Set<String> = new Set();
+  return (name: string, fn: Function) => {
+    if (refNames.has(name)) {
+      throw new OwlError(
+        `Cannot set the same ref more than once in the same component, ref "${name}" was set multiple times in ${node.name}`
+      );
+    }
+    refNames.add(name);
+    return fn;
+  };
+}
+
+export const helpers = {
+  withDefault,
+  zero: Symbol("zero"),
+  isBoundary,
+  callSlot,
+  capture,
+  withKey,
+  prepareList,
+  setContextValue,
+  shallowEqual,
+  toNumber,
+  validateProps,
+  LazyValue,
+  safeOutput,
+  createCatcher,
+  markRaw,
+  OwlError,
+  makeRefWrapper,
+};

src/runtime/template_set.ts

@@ -1,12 +1,11 @@
-import { createBlock, html, list, multi, text, toggler, comment } from "../blockdom";
-import { compile, Template } from "../compiler";
-import { markRaw } from "../reactivity";
-import { Portal } from "../portal";
-import { component, getCurrent } from "../component/component_node";
+import { compile, Template, TemplateFunction } from "../compiler";
+import { comment, createBlock, html, list, multi, text, toggler } from "./blockdom";
+import { getCurrent } from "./component_node";
+import { Portal, portalTemplate } from "./portal";
 import { helpers } from "./template_helpers";
-import { globalTemplates } from "../utils";
+import { OwlError } from "./error_handling";
 
-const bdom = { text, createBlock, list, multi, html, toggler, component, comment };
+const bdom = { text, createBlock, list, multi, html, toggler, comment };
 
 function parseXML(xml: string): Document {
   const parser = new DOMParser();
@@ -33,27 +32,11 @@ function parseXML(xml: string): Document {
         }
       }
     }
-    throw new Error(msg);
+    throw new OwlError(msg);
   }
   return doc;
 }
 
-/**
- * Returns the helpers object that will be injected in each template closure
- * function
- */
-function makeHelpers(getTemplate: (name: string) => Template): any {
-  return Object.assign({}, helpers, {
-    Portal,
-    markRaw,
-    getTemplate,
-    call: (owner: any, subTemplate: string, ctx: any, parent: any, key: any) => {
-      const template = getTemplate(subTemplate);
-      return toggler(subTemplate, template.call(owner, ctx, parent, key));
-    },
-  });
-}
-
 export interface TemplateSetConfig {
   dev?: boolean;
   translatableAttributes?: string[];
@@ -62,12 +45,15 @@ export interface TemplateSetConfig {
 }
 
 export class TemplateSet {
+  static registerTemplate(name: string, fn: TemplateFunction) {
+    globalTemplates[name] = fn;
+  }
   dev: boolean;
   rawTemplates: typeof globalTemplates = Object.create(globalTemplates);
   templates: { [name: string]: Template } = {};
   translateFn?: (s: string) => string;
   translatableAttributes?: string[];
-  helpers: any;
+  Portal = Portal;
 
   constructor(config: TemplateSetConfig = {}) {
     this.dev = config.dev || false;
@@ -76,21 +62,27 @@ export class TemplateSet {
     if (config.templates) {
       this.addTemplates(config.templates);
     }
-    this.helpers = makeHelpers(this.getTemplate.bind(this));
   }
 
-  addTemplate(
-    name: string,
-    template: string | Element,
-    options: { allowDuplicate?: boolean } = {}
-  ) {
-    if (name in this.rawTemplates && !options.allowDuplicate) {
-      throw new Error(`Template ${name} already defined`);
+  addTemplate(name: string, template: string | Element) {
+    if (name in this.rawTemplates) {
+      const rawTemplate = this.rawTemplates[name];
+      const currentAsString =
+        typeof rawTemplate === "string"
+          ? rawTemplate
+          : rawTemplate instanceof Element
+          ? rawTemplate.outerHTML
+          : rawTemplate.toString();
+      const newAsString = typeof template === "string" ? template : template.outerHTML;
+      if (currentAsString === newAsString) {
+        return;
+      }
+      throw new OwlError(`Template ${name} already defined with different content`);
     }
     this.rawTemplates[name] = template;
   }
 
-  addTemplates(xml: string | Document, options: { allowDuplicate?: boolean } = {}) {
+  addTemplates(xml: string | Document) {
     if (!xml) {
       // empty string
       return;
@@ -98,7 +90,7 @@ export class TemplateSet {
     xml = xml instanceof Document ? xml : parseXML(xml);
     for (const template of xml.querySelectorAll("[t-name]")) {
       const name = template.getAttribute("t-name")!;
-      this.addTemplate(name, template, options);
+      this.addTemplate(name, template);
     }
   }
 
@@ -111,27 +103,44 @@ export class TemplateSet {
           const componentName = getCurrent().component.constructor.name;
           extraInfo = ` (for component "${componentName}")`;
         } catch {}
-        throw new Error(`Missing template: "${name}"${extraInfo}`);
+        throw new OwlError(`Missing template: "${name}"${extraInfo}`);
       }
-      const templateFn = this._compileTemplate(name, rawTemplate);
+      const isFn = typeof rawTemplate === "function" && !(rawTemplate instanceof Element);
+      const templateFn = isFn ? rawTemplate : this._compileTemplate(name, rawTemplate);
       // first add a function to lazily get the template, in case there is a
       // recursive call to the template name
       const templates = this.templates;
       this.templates[name] = function (context, parent) {
         return templates[name].call(this, context, parent);
       };
-      const template = templateFn(bdom, this.helpers);
+      const template = templateFn(this, bdom, helpers);
       this.templates[name] = template;
     }
     return this.templates[name];
   }
 
-  _compileTemplate(name: string, template: string | Element) {
-    return compile(template, {
-      name,
-      dev: this.dev,
-      translateFn: this.translateFn,
-      translatableAttributes: this.translatableAttributes,
-    });
+  _compileTemplate(name: string, template: string | Element): ReturnType<typeof compile> {
+    throw new OwlError(`Unable to compile a template. Please use owl full build instead`);
+  }
+
+  callTemplate(owner: any, subTemplate: string, ctx: any, parent: any, key: any): any {
+    const template = this.getTemplate(subTemplate);
+    return toggler(subTemplate, template.call(owner, ctx, parent, key));
   }
 }
+
+// -----------------------------------------------------------------------------
+//  xml tag helper
+// -----------------------------------------------------------------------------
+export const globalTemplates: { [key: string]: string | Element | TemplateFunction } = {};
+
+export function xml(...args: Parameters<typeof String.raw>) {
+  const name = `__template__${xml.nextId++}`;
+  const value = String.raw(...args);
+  globalTemplates[name] = value;
+  return name;
+}
+
+xml.nextId = 1;
+
+TemplateSet.registerTemplate("__portal__", portalTemplate);

src/runtime/utils.ts

@@ -1,3 +1,4 @@
+import { OwlError } from "./error_handling";
 export type Callback = () => void;
 
 /**
@@ -15,22 +16,30 @@ export function batched(callback: Callback): Callback {
     await Promise.resolve();
     if (!called) {
       called = true;
-      callback();
       // wait for all calls in this microtick to fall through before resetting "called"
-      // so that only the first call to the batched function calls the original callback
-      await Promise.resolve();
-      called = false;
+      // so that only the first call to the batched function calls the original callback.
+      // Schedule this before calling the callback so that calls to the batched function
+      // within the callback will proceed only after resetting called to false, and have
+      // a chance to execute the callback again
+      Promise.resolve().then(() => (called = false));
+      callback();
     }
   };
 }
 
 export function validateTarget(target: HTMLElement) {
-  if (!(target instanceof HTMLElement)) {
-    throw new Error("Cannot mount component: the target is not a valid DOM element");
-  }
-  if (!document.body.contains(target)) {
-    throw new Error("Cannot mount a component on a detached dom node");
+  // Get the document and HTMLElement corresponding to the target to allow mounting in iframes
+  const document = target && target.ownerDocument;
+  if (document) {
+    const HTMLElement = document.defaultView!.HTMLElement;
+    if (target instanceof HTMLElement) {
+      if (!document.body.contains(target)) {
+        throw new OwlError("Cannot mount a component on a detached dom node");
+      }
+      return;
+    }
   }
+  throw new OwlError("Cannot mount component: the target is not a valid DOM element");
 }
 
 export class EventBus extends EventTarget {
@@ -52,7 +61,7 @@ export function whenReady(fn?: any): Promise<void> {
 export async function loadFile(url: string): Promise<string> {
   const result = await fetch(url);
   if (!result.ok) {
-    throw new Error("Error while fetching xml templates");
+    throw new OwlError("Error while fetching xml templates");
   }
   return await result.text();
 }
@@ -71,17 +80,3 @@ export class Markup extends String {}
 export function markup(value: any) {
   return new Markup(value);
 }
-
-// -----------------------------------------------------------------------------
-//  xml tag helper
-// -----------------------------------------------------------------------------
-export const globalTemplates: { [key: string]: string | Element } = {};
-
-export function xml(...args: Parameters<typeof String.raw>) {
-  const name = `__template__${xml.nextId++}`;
-  const value = String.raw(...args);
-  globalTemplates[name] = value;
-  return name;
-}
-
-xml.nextId = 1;

src/runtime/validation.ts

@@ -0,0 +1,171 @@
+import { OwlError } from "./error_handling";
+import { toRaw } from "./reactivity";
+
+type BaseType =
+  | typeof String
+  | typeof Boolean
+  | typeof Number
+  | typeof Date
+  | typeof Object
+  | typeof Array
+  | true
+  | "*";
+
+interface TypeInfo {
+  type?: TypeDescription;
+  optional?: boolean;
+  validate?: Function;
+  shape?: Schema;
+  element?: TypeDescription;
+}
+
+type ValueType = { value: any };
+
+type TypeDescription = BaseType | TypeInfo | ValueType | TypeDescription[];
+type SimplifiedSchema = string[];
+type NormalizedSchema = { [key: string]: TypeDescription };
+export type Schema = SimplifiedSchema | NormalizedSchema;
+
+// -----------------------------------------------------------------------------
+// helpers
+// -----------------------------------------------------------------------------
+const isUnionType = (t: TypeDescription): t is TypeDescription[] => Array.isArray(t);
+const isBaseType = (t: TypeDescription): t is BaseType => typeof t !== "object";
+const isValueType = (t: TypeDescription): t is ValueType =>
+  typeof t === "object" && t && "value" in t;
+
+export function isOptional(t: TypeDescription): Boolean {
+  return typeof t === "object" && "optional" in t ? t.optional || false : false;
+}
+
+function describeType(type: BaseType): string {
+  return type === "*" || type === true ? "value" : type.name.toLowerCase();
+}
+
+function describe(info: TypeDescription): string {
+  if (isBaseType(info)) {
+    return describeType(info);
+  } else if (isUnionType(info)) {
+    return info.map(describe).join(" or ");
+  } else if (isValueType(info)) {
+    return String(info.value);
+  }
+  if ("element" in info) {
+    return `list of ${describe({ type: info.element, optional: false })}s`;
+  }
+  if ("shape" in (info as TypeInfo)) {
+    return `object`;
+  }
+  return describe(info.type || "*");
+}
+
+function toSchema(spec: SimplifiedSchema): NormalizedSchema {
+  return Object.fromEntries(
+    spec.map((e) =>
+      e.endsWith("?") ? [e.slice(0, -1), { optional: true }] : [e, { type: "*", optional: false }]
+    )
+  );
+}
+
+/**
+ * Main validate function
+ */
+export function validate(obj: { [key: string]: any }, spec: Schema) {
+  let errors = validateSchema(obj, spec);
+  if (errors.length) {
+    throw new OwlError("Invalid object: " + errors.join(", "));
+  }
+}
+
+/**
+ * Helper validate function, to get the list of errors. useful if one want to
+ * manipulate the errors without parsing an error object
+ */
+export function validateSchema(obj: { [key: string]: any }, schema: Schema): string[] {
+  if (Array.isArray(schema)) {
+    schema = toSchema(schema);
+  }
+  obj = toRaw(obj);
+  let errors = [];
+  // check if each value in obj has correct shape
+  for (let key in obj) {
+    if (key in schema) {
+      let result = validateType(key, obj[key], schema[key]);
+      if (result) {
+        errors.push(result);
+      }
+    } else if (!("*" in schema)) {
+      errors.push(`unknown key '${key}'`);
+    }
+  }
+  // check that all specified keys are defined in obj
+  for (let key in schema) {
+    const spec = schema[key];
+    if (key !== "*" && !isOptional(spec) && !(key in obj)) {
+      const isObj = typeof spec === "object" && !Array.isArray(spec);
+      const isAny = spec === "*" || (isObj && "type" in spec ? spec.type === "*" : isObj);
+      let detail = isAny ? "" : ` (should be a ${describe(spec)})`;
+      errors.push(`'${key}' is missing${detail}`);
+    }
+  }
+  return errors;
+}
+
+function validateBaseType(key: string, value: any, type: BaseType): string | null {
+  if (typeof type === "function") {
+    if (typeof value === "object") {
+      if (!(value instanceof type)) {
+        return `'${key}' is not a ${describeType(type)}`;
+      }
+    } else if (typeof value !== type.name.toLowerCase()) {
+      return `'${key}' is not a ${describeType(type)}`;
+    }
+  }
+  return null;
+}
+
+function validateArrayType(key: string, value: any, descr: TypeDescription): string | null {
+  if (!Array.isArray(value)) {
+    return `'${key}' is not a list of ${describe(descr)}s`;
+  }
+  for (let i = 0; i < value.length; i++) {
+    const error = validateType(`${key}[${i}]`, value[i], descr);
+    if (error) {
+      return error;
+    }
+  }
+  return null;
+}
+
+function validateType(key: string, value: any, descr: TypeDescription): string | null {
+  if (value === undefined) {
+    return isOptional(descr) ? null : `'${key}' is undefined (should be a ${describe(descr)})`;
+  } else if (isBaseType(descr)) {
+    return validateBaseType(key, value, descr);
+  } else if (isValueType(descr)) {
+    return value === descr.value ? null : `'${key}' is not equal to '${descr.value}'`;
+  } else if (isUnionType(descr)) {
+    let validDescr = descr.find((p) => !validateType(key, value, p));
+    return validDescr ? null : `'${key}' is not a ${describe(descr)}`;
+  }
+  let result: string | null = null;
+  if ("element" in descr) {
+    result = validateArrayType(key, value, descr.element!);
+  } else if ("shape" in descr && !result) {
+    if (typeof value !== "object" || Array.isArray(value)) {
+      result = `'${key}' is not an object`;
+    } else {
+      const errors = validateSchema(value, descr.shape!);
+      if (errors.length) {
+        result = `'${key}' has not the correct shape (${errors.join(", ")})`;
+      }
+    }
+  }
+  if ("type" in descr && !result) {
+    result = validateType(key, value, descr.type!);
+  }
+  if ("validate" in descr && !result) {
+    result = !descr.validate!(value) ? `'${key}' is not valid` : null;
+  }
+  return result;
+}

src/version.ts

@@ -0,0 +1,2 @@
+// do not modify manually. This value is updated by the release script.
+export const version = "2.1.0";

tests/__snapshots__/reactivity.test.ts.snap

@@ -47,16 +47,17 @@ exports[`Reactivity: useState concurrent renderings 3`] = `
 `;
 
 exports[`Reactivity: useState destroyed component before being mounted is inactive 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
     if (ctx['state'].flag) {
-      b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+      b2 = comp1({}, key + \`__1\`, node, this, null);
     }
     return block1([], [b2]);
   }
@@ -64,9 +65,9 @@ exports[`Reactivity: useState destroyed component before being mounted is inacti
 `;
 
 exports[`Reactivity: useState destroyed component before being mounted is inactive 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -78,16 +79,17 @@ exports[`Reactivity: useState destroyed component before being mounted is inacti
 `;
 
 exports[`Reactivity: useState destroyed component is inactive 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
     if (ctx['state'].flag) {
-      b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+      b2 = comp1({}, key + \`__1\`, node, this, null);
     }
     return block1([], [b2]);
   }
@@ -95,9 +97,9 @@ exports[`Reactivity: useState destroyed component is inactive 1`] = `
 `;
 
 exports[`Reactivity: useState destroyed component is inactive 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -109,9 +111,9 @@ exports[`Reactivity: useState destroyed component is inactive 2`] = `
 `;
 
 exports[`Reactivity: useState one components can subscribe twice to same context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
   
@@ -124,14 +126,15 @@ exports[`Reactivity: useState one components can subscribe twice to same context
 `;
 
 exports[`Reactivity: useState parent and children subscribed to same context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    const b2 = comp1({}, key + \`__1\`, node, this, null);
     let txt1 = ctx['contextObj'].b;
     return block1([txt1], [b2]);
   }
@@ -139,9 +142,9 @@ exports[`Reactivity: useState parent and children subscribed to same context 1`]
 `;
 
 exports[`Reactivity: useState parent and children subscribed to same context 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -216,24 +219,26 @@ exports[`Reactivity: useState several nodes on different level use same context
 `;
 
 exports[`Reactivity: useState two components are updated in parallel 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
+  const comp2 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
-    const b3 = component(\`Child\`, {}, key + \`__2\`, node, ctx);
+    const b2 = comp1({}, key + \`__1\`, node, this, null);
+    const b3 = comp2({}, key + \`__2\`, node, this, null);
     return block1([], [b2, b3]);
   }
 }"
 `;
 
 exports[`Reactivity: useState two components are updated in parallel 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -245,24 +250,26 @@ exports[`Reactivity: useState two components are updated in parallel 2`] = `
 `;
 
 exports[`Reactivity: useState two components can subscribe to same context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
+  const comp2 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
-    const b3 = component(\`Child\`, {}, key + \`__2\`, node, ctx);
+    const b2 = comp1({}, key + \`__1\`, node, this, null);
+    const b3 = comp2({}, key + \`__2\`, node, this, null);
     return block1([], [b2, b3]);
   }
 }"
 `;
 
 exports[`Reactivity: useState two components can subscribe to same context 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -274,24 +281,26 @@ exports[`Reactivity: useState two components can subscribe to same context 2`] =
 `;
 
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
+  const comp2 = app.createComponent(\`Parent\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
-    const b3 = component(\`Parent\`, {}, key + \`__2\`, node, ctx);
+    const b2 = comp1({}, key + \`__1\`, node, this, null);
+    const b3 = comp2({}, key + \`__2\`, node, this, null);
     return block1([], [b2, b3]);
   }
 }"
 `;
 
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -303,23 +312,24 @@ exports[`Reactivity: useState two independent components on different levels are
 `;
 
 exports[`Reactivity: useState two independent components on different levels are updated in parallel 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const comp1 = app.createComponent(\`Child\`, true, false, false, []);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
+    const b2 = comp1({}, key + \`__1\`, node, this, null);
     return block1([], [b2]);
   }
 }"
 `;
 
 exports[`Reactivity: useState useContext=useState hook is reactive, for one component 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -331,10 +341,11 @@ exports[`Reactivity: useState useContext=useState hook is reactive, for one comp
 `;
 
 exports[`Reactivity: useState useless atoms should be deleted 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
+  const comp1 = app.createComponent(\`Quantity\`, true, false, false, [\\"id\\"]);
   
   let block1 = createBlock(\`<div><block-child-0/> Total: <block-text-0/> Count: <block-text-1/></div>\`);
   
@@ -344,7 +355,7 @@ exports[`Reactivity: useState useless atoms should be deleted 1`] = `
     for (let i1 = 0; i1 < l_block2; i1++) {
       ctx[\`id\`] = v_block2[i1];
       const key1 = ctx['id'];
-      c_block2[i1] = withKey(component(\`Quantity\`, {id: ctx['id']}, key + \`__1__\${key1}\`, node, ctx), key1);
+      c_block2[i1] = withKey(comp1({id: ctx['id']}, key + \`__1__\${key1}\`, node, this, null), key1);
     }
     ctx = ctx.__proto__;
     const b2 = list(c_block2);
@@ -356,9 +367,9 @@ exports[`Reactivity: useState useless atoms should be deleted 1`] = `
 `;
 
 exports[`Reactivity: useState useless atoms should be deleted 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -370,9 +381,9 @@ exports[`Reactivity: useState useless atoms should be deleted 2`] = `
 `;
 
 exports[`Reactivity: useState very simple use, with initial value 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   

tests/app/__snapshots__/app.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`app App supports env with getters/setters 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/> <block-text-1/></div>\`);
   
@@ -16,9 +16,9 @@ exports[`app App supports env with getters/setters 1`] = `
 `;
 
 exports[`app can configure an app with props 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -29,10 +29,23 @@ exports[`app can configure an app with props 1`] = `
 }"
 `;
 
-exports[`app destroy remove the widget from the DOM 1`] = `
-"function anonymous(bdom, helpers
+exports[`app can mount app in an iframe 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div class=\\"my-div\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
+exports[`app destroy remove the widget from the DOM 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -41,3 +54,17 @@ exports[`app destroy remove the widget from the DOM 1`] = `
   }
 }"
 `;
+
+exports[`app warnIfNoStaticProps works as expected 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div><block-text-0/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let txt1 = ctx['message'];
+    return block1([txt1]);
+  }
+}"
+`;

tests/app/app.test.ts

@@ -1,5 +1,5 @@
-import { App, Component, xml } from "../../src";
-import { status } from "../../src/component/status";
+import { App, Component, mount, xml } from "../../src";
+import { status } from "../../src/runtime/status";
 import { makeTestFixture, snapshotEverything, nextTick, elem } from "../helpers";
 
 let fixture: HTMLElement;
@@ -59,4 +59,39 @@ describe("app", () => {
     await app.mount(fixture);
     expect(fixture.innerHTML).toBe("<div>333</div>");
   });
+
+  test("warnIfNoStaticProps works as expected", async () => {
+    let originalconsoleWarn = console.warn;
+    let mockConsoleWarn = jest.fn(() => {});
+    console.warn = mockConsoleWarn;
+
+    class Root extends Component {
+      static template = xml`<div t-esc="message"/>`;
+    }
+
+    await mount(Root, fixture, { test: true, props: { messge: "hey" }, warnIfNoStaticProps: true });
+
+    console.warn = originalconsoleWarn;
+    expect(mockConsoleWarn).toBeCalledWith(
+      "Component 'Root' does not have a static props description"
+    );
+  });
+
+  test("can mount app in an iframe", async () => {
+    class SomeComponent extends Component {
+      static template = xml`<div class="my-div"/>`;
+    }
+
+    const iframe = document.createElement("iframe");
+    fixture.appendChild(iframe);
+    const app = new App(SomeComponent);
+    const iframeDoc = iframe.contentDocument!;
+    const comp = await app.mount(iframeDoc.body);
+    const div = iframeDoc.querySelector(".my-div");
+    expect(div).not.toBe(null);
+    expect(iframeDoc.contains(div)).toBe(true);
+    app.destroy();
+    expect(iframeDoc.contains(div)).toBe(false);
+    expect(status(comp)).toBe("destroyed");
+  });
 });

tests/blockdom/block.test.ts

@@ -1,4 +1,4 @@
-import { createBlock, mount, patch, remove, text } from "../../src/blockdom";
+import { createBlock, mount, patch, remove, text } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/block_attributes.test.ts

@@ -1,4 +1,4 @@
-import { mount, patch, createBlock } from "../../src/blockdom";
+import { mount, patch, createBlock } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------
@@ -145,47 +145,3 @@ test("class attribute (with a preexisting value", async () => {
   patch(tree, block([""]));
   expect(fixture.innerHTML).toBe(`<div class="tomato"></div>`);
 });
-
-describe("properties", () => {
-  test("input with value attribute", () => {
-    // render input with initial value
-    const block = createBlock(`<input block-attribute-0="value"/>`);
-
-    const tree = block(["zucchini"]);
-    mount(tree, fixture);
-    // const bnode1 = renderToBdom(template, { v: "zucchini" });
-    // const fixture = makeTestFixture();
-    // mount(bnode1, fixture);
-    const input = fixture.querySelector("input")!;
-    expect(input.value).toBe("zucchini");
-
-    // change value manually in input, to simulate user input
-    input.value = "tomato";
-    expect(input.value).toBe("tomato");
-
-    // rerender with a different value, and patch actual dom, to check that
-    // input value was properly reset by owl
-    patch(tree, block(["potato"]));
-    expect(input.value).toBe("potato");
-  });
-
-  test("input with value attribute, and undefined given", () => {
-    const block = createBlock(`<input block-attribute-0="value"/>`);
-
-    const tree = block([undefined]);
-    mount(tree, fixture);
-    const input = fixture.querySelector("input")!;
-    expect(input.value).toBe("");
-  });
-
-  test("input type=checkbox with checked attribute", () => {
-    // render input with initial value
-    const block = createBlock(`<input type="checkbox" block-attribute-0="checked"/>`);
-
-    const tree = block([true]);
-    mount(tree, fixture);
-    expect(fixture.innerHTML).toBe(`<input type="checkbox">`);
-    const input = fixture.querySelector("input")!;
-    expect(input.checked).toBe(true);
-  });
-});

tests/blockdom/block_event_handling.test.ts

@@ -1,4 +1,4 @@
-import { mount, createBlock, multi, config, patch } from "../../src/blockdom";
+import { mount, createBlock, multi, config, patch } from "../../src/runtime/blockdom";
 // import { defaultHandler, setupMainHandler } from "../../src/bdom/block";
 import { makeTestFixture } from "./helpers";
 

tests/blockdom/block_properties.test.ts

@@ -0,0 +1,70 @@
+import { mount, patch, createBlock } from "../../src/runtime/blockdom";
+import { makeTestFixture } from "./helpers";
+
+//------------------------------------------------------------------------------
+// Setup and helpers
+//------------------------------------------------------------------------------
+
+let fixture: HTMLElement;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+});
+
+afterEach(() => {
+  fixture.remove();
+});
+
+test("input with value property", () => {
+  // render input with initial value
+  const block = createBlock(`<input block-property-0="value"/>`);
+
+  const tree = block(["zucchini"]);
+  mount(tree, fixture);
+  // const bnode1 = renderToBdom(template, { v: "zucchini" });
+  // const fixture = makeTestFixture();
+  // mount(bnode1, fixture);
+  const input = fixture.querySelector("input")!;
+  expect(input.value).toBe("zucchini");
+
+  // change value manually in input, to simulate user input
+  input.value = "tomato";
+  expect(input.value).toBe("tomato");
+
+  // rerender with a different value, and patch actual dom, to check that
+  // input value was properly reset by owl
+  patch(tree, block(["potato"]));
+  expect(input.value).toBe("potato");
+});
+
+test("input with value property, and falsy value given", () => {
+  const block = createBlock(`<input block-property-0="value"/>`);
+
+  const tree = block([undefined]);
+  mount(tree, fixture);
+  const input = fixture.querySelector("input")!;
+  expect(input.value).toBe("");
+
+  patch(tree, block([null]));
+  expect(input.value).toBe("");
+
+  patch(tree, block([0]));
+  expect(input.value).toBe("0");
+
+  patch(tree, block([""]));
+  expect(input.value).toBe("");
+
+  patch(tree, block([false]));
+  expect(input.value).toBe("");
+});
+
+test("input type=checkbox with checked property", () => {
+  // render input with initial value
+  const block = createBlock(`<input type="checkbox" block-property-0="checked"/>`);
+
+  const tree = block([true]);
+  mount(tree, fixture);
+  expect(fixture.innerHTML).toBe(`<input type="checkbox">`);
+  const input = fixture.querySelector("input")!;
+  expect(input.checked).toBe(true);
+});

tests/blockdom/block_refs.test.ts

@@ -1,4 +1,4 @@
-import { createBlock, mount, patch, remove } from "../../src/blockdom";
+import { createBlock, mount, patch, remove } from "../../src/runtime/blockdom";
 import { logStep } from "../helpers";
 import { makeTestFixture } from "./helpers";
 

tests/blockdom/comment.test.ts

@@ -1,4 +1,4 @@
-import { comment, mount } from "../../src/blockdom";
+import { comment, mount } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/event_catcher.test.ts

@@ -1,6 +1,6 @@
-import { config, createBlock, createCatcher, mount } from "../../src/blockdom";
+import { config, createBlock, createCatcher, mount } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
-import { mainEventHandler } from "../../src/component/handler";
+import { mainEventHandler } from "../../src/runtime/event_handling";
 
 //------------------------------------------------------------------------------
 // Setup and helpers

tests/blockdom/html.test.ts

@@ -1,4 +1,4 @@
-import { html, mount, patch, text } from "../../src/blockdom";
+import { html, mount, patch, text } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/list.test.ts

@@ -1,4 +1,13 @@
-import { list, mount, multi, patch, text, createBlock, VNode, withKey } from "../../src/blockdom";
+import {
+  list,
+  mount,
+  multi,
+  patch,
+  text,
+  createBlock,
+  VNode,
+  withKey,
+} from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/multi.test.ts

@@ -1,4 +1,4 @@
-import { mount, multi, patch, text, createBlock } from "../../src/blockdom";
+import { mount, multi, patch, text, createBlock } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/namespace.test.ts

@@ -1,4 +1,4 @@
-import { createBlock, mount } from "../../src/blockdom";
+import { createBlock, mount } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/remove_hook.test.ts

@@ -1,4 +1,4 @@
-import { createBlock, mount, multi, patch } from "../../src/blockdom";
+import { createBlock, mount, multi, patch } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/text.test.ts

@@ -1,4 +1,4 @@
-import { mount, patch, remove, text } from "../../src/blockdom";
+import { mount, patch, remove, text } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/blockdom/toggler.test.ts

@@ -1,4 +1,4 @@
-import { createBlock, mount, patch, text, toggler } from "../../src/blockdom";
+import { createBlock, mount, patch, text, toggler } from "../../src/runtime/blockdom";
 import { makeTestFixture } from "./helpers";
 
 //------------------------------------------------------------------------------

tests/compiler/__snapshots__/attributes.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`attributes changing a class with t-att-class (preexisting class 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"hoy\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -15,9 +15,9 @@ exports[`attributes changing a class with t-att-class (preexisting class 1`] = `
 `;
 
 exports[`attributes changing a class with t-att-class 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -28,24 +28,10 @@ exports[`attributes changing a class with t-att-class 1`] = `
 }"
 `;
 
-exports[`attributes changing an attribute with t-att- 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<div block-attribute-0=\\"value\\"/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['v'];
-    return block1([attr1]);
-  }
-}"
-`;
-
 exports[`attributes class and t-att-class should combine together 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\" class=\\"hello\\"/>\`);
   
@@ -57,9 +43,9 @@ exports[`attributes class and t-att-class should combine together 1`] = `
 `;
 
 exports[`attributes class and t-attf-class with ternary operation 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -71,9 +57,9 @@ exports[`attributes class and t-attf-class with ternary operation 1`] = `
 `;
 
 exports[`attributes dynamic attribute evaluating to 0 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -85,9 +71,9 @@ exports[`attributes dynamic attribute evaluating to 0 1`] = `
 `;
 
 exports[`attributes dynamic attribute falsy variable  1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -99,9 +85,9 @@ exports[`attributes dynamic attribute falsy variable  1`] = `
 `;
 
 exports[`attributes dynamic attribute with a dash 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"data-action-id\\"/>\`);
   
@@ -113,9 +99,9 @@ exports[`attributes dynamic attribute with a dash 1`] = `
 `;
 
 exports[`attributes dynamic attributes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -126,10 +112,24 @@ exports[`attributes dynamic attributes 1`] = `
 }"
 `;
 
-exports[`attributes dynamic class attribute 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes dynamic attributes with backticks 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = \`bar\`;
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes dynamic class attribute 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -141,9 +141,9 @@ exports[`attributes dynamic class attribute 1`] = `
 `;
 
 exports[`attributes dynamic class attribute evaluating to 0 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -154,10 +154,52 @@ exports[`attributes dynamic class attribute evaluating to 0 1`] = `
 }"
 `;
 
-exports[`attributes dynamic empty class attribute 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes dynamic class attribute that starts and ends with a space 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = ctx['c'];
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes dynamic class attribute which is only a space 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = ctx['c'];
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes dynamic class attribute with multiple consecutive spaces 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = ctx['c'];
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes dynamic empty class attribute 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -169,9 +211,9 @@ exports[`attributes dynamic empty class attribute 1`] = `
 `;
 
 exports[`attributes dynamic formatted attributes with a dash 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"aria-label\\"/>\`);
   
@@ -183,9 +225,9 @@ exports[`attributes dynamic formatted attributes with a dash 1`] = `
 `;
 
 exports[`attributes dynamic undefined class attribute 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -197,9 +239,9 @@ exports[`attributes dynamic undefined class attribute 1`] = `
 `;
 
 exports[`attributes dynamic undefined generic attribute 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"thing\\"/>\`);
   
@@ -211,9 +253,9 @@ exports[`attributes dynamic undefined generic attribute 1`] = `
 `;
 
 exports[`attributes fixed variable 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -225,9 +267,9 @@ exports[`attributes fixed variable 1`] = `
 `;
 
 exports[`attributes format expression 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -239,9 +281,9 @@ exports[`attributes format expression 1`] = `
 `;
 
 exports[`attributes format literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -253,9 +295,9 @@ exports[`attributes format literal 1`] = `
 `;
 
 exports[`attributes format multiple 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -267,9 +309,9 @@ exports[`attributes format multiple 1`] = `
 `;
 
 exports[`attributes format value 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -281,9 +323,9 @@ exports[`attributes format value 1`] = `
 `;
 
 exports[`attributes from object variables set previously 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-attribute-0=\\"class\\"/></div>\`);
@@ -299,9 +341,9 @@ exports[`attributes from object variables set previously 1`] = `
 `;
 
 exports[`attributes from variables set previously (no external node) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span block-attribute-0=\\"class\\"/>\`);
@@ -317,9 +359,9 @@ exports[`attributes from variables set previously (no external node) 1`] = `
 `;
 
 exports[`attributes from variables set previously 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-attribute-0=\\"class\\"/></div>\`);
@@ -335,9 +377,9 @@ exports[`attributes from variables set previously 1`] = `
 `;
 
 exports[`attributes object 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -349,9 +391,9 @@ exports[`attributes object 1`] = `
 `;
 
 exports[`attributes static attributes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div foo=\\"a\\" bar=\\"b\\" baz=\\"c\\"/>\`);
   
@@ -362,9 +404,9 @@ exports[`attributes static attributes 1`] = `
 `;
 
 exports[`attributes static attributes on void elements 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<img src=\\"/test.skip.jpg\\" alt=\\"Test\\"/>\`);
   
@@ -374,10 +416,36 @@ exports[`attributes static attributes on void elements 1`] = `
 }"
 `;
 
-exports[`attributes static attributes with dashes 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes static attributes with backslash or backtick 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div foo=\\"\\\\\\\\a\\" bar=\\"\\\\\\\\n\\" baz=\\"\\\\\`\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
+exports[`attributes static attributes with backticks 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div foo=\\"\\\\\`bar\\\\\`\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
+exports[`attributes static attributes with dashes 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div aria-label=\\"Close\\"/>\`);
   
@@ -387,10 +455,24 @@ exports[`attributes static attributes with dashes 1`] = `
 }"
 `;
 
-exports[`attributes t-att-class and class should combine together 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes string interpolation, alternate syntax 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = \`b\${ctx['value']}r\`;
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes t-att-class and class should combine together 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -402,9 +484,9 @@ exports[`attributes t-att-class and class should combine together 1`] = `
 `;
 
 exports[`attributes t-att-class with multiple classes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -416,9 +498,9 @@ exports[`attributes t-att-class with multiple classes 1`] = `
 `;
 
 exports[`attributes t-att-class with multiple classes 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -429,10 +511,24 @@ exports[`attributes t-att-class with multiple classes 2`] = `
 }"
 `;
 
-exports[`attributes t-att-class with multiple classes, some of which are duplicate 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes t-att-class with multiple classes 3`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = {'a  b  c':ctx['value']};
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes t-att-class with multiple classes, some of which are duplicate 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -444,9 +540,9 @@ exports[`attributes t-att-class with multiple classes, some of which are duplica
 `;
 
 exports[`attributes t-att-class with object 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"static\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -457,10 +553,38 @@ exports[`attributes t-att-class with object 1`] = `
 }"
 `;
 
-exports[`attributes t-attf-class 1`] = `
-"function anonymous(bdom, helpers
+exports[`attributes t-att-class with object 2`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = {' a ':ctx['value']};
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes t-att-class with object 3`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = {' ':ctx['value']};
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`attributes t-attf-class 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -472,9 +596,9 @@ exports[`attributes t-attf-class 1`] = `
 `;
 
 exports[`attributes t-attf-class should combine with class 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -486,9 +610,9 @@ exports[`attributes t-attf-class should combine with class 1`] = `
 `;
 
 exports[`attributes t-attf-class with multiple classes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -500,9 +624,9 @@ exports[`attributes t-attf-class with multiple classes 1`] = `
 `;
 
 exports[`attributes t-attf-class with multiple classes separated by multiple spaces 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -514,9 +638,9 @@ exports[`attributes t-attf-class with multiple classes separated by multiple spa
 `;
 
 exports[`attributes tuple literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -528,9 +652,9 @@ exports[`attributes tuple literal 1`] = `
 `;
 
 exports[`attributes tuple variable 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -542,9 +666,9 @@ exports[`attributes tuple variable 1`] = `
 `;
 
 exports[`attributes two classes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"a b\\"/>\`);
   
@@ -555,9 +679,9 @@ exports[`attributes two classes 1`] = `
 `;
 
 exports[`attributes two dynamic attributes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\" block-attribute-1=\\"bar\\"/>\`);
   
@@ -570,9 +694,9 @@ exports[`attributes two dynamic attributes 1`] = `
 `;
 
 exports[`attributes updating classes (with obj notation) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"hoy\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -584,9 +708,9 @@ exports[`attributes updating classes (with obj notation) 1`] = `
 `;
 
 exports[`attributes various escapes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div foo=\\"&lt;foo\\" block-attribute-0=\\"bar\\" block-attribute-1=\\"baz\\" block-attributes=\\"2\\"/>\`);
   
@@ -600,9 +724,9 @@ exports[`attributes various escapes 1`] = `
 `;
 
 exports[`attributes various escapes 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div> &lt; </div>\`);
   
@@ -611,86 +735,3 @@ exports[`attributes various escapes 2 1`] = `
   }
 }"
 `;
-
-exports[`special cases for some specific html attributes/properties input of type checkbox with t-att-indeterminate 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<input type=\\"checkbox\\" block-attribute-0=\\"indeterminate\\"/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['v'];
-    return block1([attr1]);
-  }
-}"
-`;
-
-exports[`special cases for some specific html attributes/properties input type= checkbox, with t-att-checked 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<input type=\\"checkbox\\" block-attribute-0=\\"checked\\"/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['flag'];
-    return block1([attr1]);
-  }
-}"
-`;
-
-exports[`special cases for some specific html attributes/properties input with t-att-value 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<input block-attribute-0=\\"value\\"/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['v'];
-    return block1([attr1]);
-  }
-}"
-`;
-
-exports[`special cases for some specific html attributes/properties select with t-att-value 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<select block-attribute-0=\\"value\\"><option value=\\"potato\\">Potato</option><option value=\\"tomato\\">Tomato</option><option value=\\"onion\\">Onion</option></select>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['value'];
-    return block1([attr1]);
-  }
-}"
-`;
-
-exports[`special cases for some specific html attributes/properties textarea with t-att-value 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<textarea block-attribute-0=\\"value\\"/>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    let attr1 = ctx['v'];
-    return block1([attr1]);
-  }
-}"
-`;
-
-exports[`special cases for some specific html attributes/properties various boolean html attributes 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  
-  let block1 = createBlock(\`<div><input type=\\"checkbox\\" checked=\\"checked\\"/><input checked=\\"checked\\"/><div checked=\\"checked\\"/><div selected=\\"selected\\"/><option selected=\\"selected\\" other=\\"1\\"/><input readonly=\\"readonly\\"/><button disabled=\\"disabled\\"/></div>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    return block1();
-  }
-}"
-`;

tests/compiler/__snapshots__/comments.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`comments only a comment 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return comment(\` comment\`);
@@ -12,9 +12,9 @@ exports[`comments only a comment 1`] = `
 `;
 
 exports[`comments properly handle comments 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>hello <!-- comment-->owl</div>\`);
   
@@ -25,9 +25,9 @@ exports[`comments properly handle comments 1`] = `
 `;
 
 exports[`comments properly handle comments between t-if/t-else 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span>true</span>\`);

tests/compiler/__snapshots__/event_handling.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-on can bind event handler 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -15,9 +15,9 @@ exports[`t-on can bind event handler 1`] = `
 `;
 
 exports[`t-on can bind handlers with arguments 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -30,9 +30,9 @@ exports[`t-on can bind handlers with arguments 1`] = `
 `;
 
 exports[`t-on can bind handlers with empty  object 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -45,9 +45,9 @@ exports[`t-on can bind handlers with empty  object 1`] = `
 `;
 
 exports[`t-on can bind handlers with empty object (with non empty inner string) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -60,9 +60,9 @@ exports[`t-on can bind handlers with empty object (with non empty inner string)
 `;
 
 exports[`t-on can bind handlers with empty object (with non empty inner string) 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<ul><block-child-0/></ul>\`);
@@ -87,9 +87,9 @@ exports[`t-on can bind handlers with empty object (with non empty inner string)
 `;
 
 exports[`t-on can bind handlers with object arguments 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -102,9 +102,9 @@ exports[`t-on can bind handlers with object arguments 1`] = `
 `;
 
 exports[`t-on can bind two event handlers 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\" block-handler-1=\\"dblclick\\">Click</button>\`);
   
@@ -117,9 +117,9 @@ exports[`t-on can bind two event handlers 1`] = `
 `;
 
 exports[`t-on handler is bound to proper owner 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -131,9 +131,9 @@ exports[`t-on handler is bound to proper owner 1`] = `
 `;
 
 exports[`t-on handler is bound to proper owner, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block2 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
@@ -153,11 +153,10 @@ exports[`t-on handler is bound to proper owner, part 2 1`] = `
 `;
 
 exports[`t-on handler is bound to proper owner, part 3 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     return callTemplate_1.call(this, ctx, node, key + \`__1\`);
@@ -166,9 +165,9 @@ exports[`t-on handler is bound to proper owner, part 3 1`] = `
 `;
 
 exports[`t-on handler is bound to proper owner, part 3 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -180,11 +179,11 @@ exports[`t-on handler is bound to proper owner, part 3 2`] = `
 `;
 
 exports[`t-on handler is bound to proper owner, part 4 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -204,9 +203,9 @@ exports[`t-on handler is bound to proper owner, part 4 1`] = `
 `;
 
 exports[`t-on handler is bound to proper owner, part 4 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -218,9 +217,9 @@ exports[`t-on handler is bound to proper owner, part 4 2`] = `
 `;
 
 exports[`t-on receive event in first argument 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -232,9 +231,9 @@ exports[`t-on receive event in first argument 1`] = `
 `;
 
 exports[`t-on t-on modifiers (native listener) basic support for native listener 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"myClass\\" block-handler-0=\\"click\\"><button block-handler-1=\\"click\\">Button</button></div>\`);
   
@@ -247,9 +246,9 @@ exports[`t-on t-on modifiers (native listener) basic support for native listener
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on combined with t-esc 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click\\"><block-text-1/></button></div>\`);
   
@@ -262,9 +261,9 @@ exports[`t-on t-on modifiers (native listener) t-on combined with t-esc 1`] = `
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on combined with t-out 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click\\"><block-child-0/></button></div>\`);
@@ -278,9 +277,9 @@ exports[`t-on t-on modifiers (native listener) t-on combined with t-out 1`] = `
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with .capture modifier 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-handler-0=\\"click.capture\\"><button block-handler-1=\\"click\\">Button</button></div>\`);
   
@@ -293,9 +292,9 @@ exports[`t-on t-on modifiers (native listener) t-on with .capture modifier 1`] =
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with empty handler (only modifiers) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click.prevent\\">Button</button></div>\`);
   
@@ -307,9 +306,9 @@ exports[`t-on t-on modifiers (native listener) t-on with empty handler (only mod
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with prevent and self modifiers (order matters) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click.prevent.self\\"><span>Button</span></button></div>\`);
   
@@ -321,9 +320,9 @@ exports[`t-on t-on modifiers (native listener) t-on with prevent and self modifi
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with prevent and/or stop modifiers 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click.prevent\\">Button 1</button><button block-handler-1=\\"click.stop\\">Button 2</button><button block-handler-2=\\"click.prevent.stop\\">Button 3</button></div>\`);
   
@@ -337,9 +336,9 @@ exports[`t-on t-on modifiers (native listener) t-on with prevent and/or stop mod
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with prevent modifier in t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -364,9 +363,9 @@ exports[`t-on t-on modifiers (native listener) t-on with prevent modifier in t-f
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with self and prevent modifiers (order matters) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click.self.prevent\\"><span>Button</span></button></div>\`);
   
@@ -378,9 +377,9 @@ exports[`t-on t-on modifiers (native listener) t-on with self and prevent modifi
 `;
 
 exports[`t-on t-on modifiers (native listener) t-on with self modifier 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click\\"><span>Button</span></button><button block-handler-1=\\"click.self\\"><span>Button</span></button></div>\`);
   
@@ -393,9 +392,9 @@ exports[`t-on t-on modifiers (native listener) t-on with self modifier 1`] = `
 `;
 
 exports[`t-on t-on modifiers (synthetic listener) basic support for synthetic 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div block-handler-0=\\"click.synthetic\\"><button block-handler-1=\\"click.synthetic\\">Button</button></div>\`);
   
@@ -408,9 +407,9 @@ exports[`t-on t-on modifiers (synthetic listener) basic support for synthetic 1`
 `;
 
 exports[`t-on t-on with inline statement (function call) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -423,9 +422,9 @@ exports[`t-on t-on with inline statement (function call) 1`] = `
 `;
 
 exports[`t-on t-on with inline statement 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -438,9 +437,9 @@ exports[`t-on t-on with inline statement 1`] = `
 `;
 
 exports[`t-on t-on with inline statement, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Toggle</button>\`);
   
@@ -453,9 +452,9 @@ exports[`t-on t-on with inline statement, part 2 1`] = `
 `;
 
 exports[`t-on t-on with inline statement, part 3 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Toggle</button>\`);
   
@@ -469,11 +468,10 @@ exports[`t-on t-on with inline statement, part 3 1`] = `
 `;
 
 exports[`t-on t-on with t-call 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -485,9 +483,9 @@ exports[`t-on t-on with t-call 1`] = `
 `;
 
 exports[`t-on t-on with t-call 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
@@ -499,11 +497,10 @@ exports[`t-on t-on with t-call 2`] = `
 `;
 
 exports[`t-on t-on, with arguments and t-call 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -515,15 +512,16 @@ exports[`t-on t-on, with arguments and t-call 1`] = `
 `;
 
 exports[`t-on t-on, with arguments and t-call 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const v1 = ctx['value'];
-    let hdlr1 = [()=>this.update(v1), ctx];
+    const v1 = ctx['this'];
+    const v2 = ctx['value'];
+    let hdlr1 = [()=>v1.update(v2), ctx];
     return block1([hdlr1]);
   }
 }"

tests/compiler/__snapshots__/misc.test.ts.snap

@@ -1,10 +1,11 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`misc complex template 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
+  const comp1 = app.createComponent(\`SlotButton\`, true, false, false, [\\"class\\",\\"slot\\"]);
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"><div block-attribute-1=\\"class\\"><div class=\\"batch_header\\"><a block-attribute-2=\\"href\\" block-attribute-3=\\"class\\" title=\\"View Batch\\"><block-text-4/><block-child-0/><i class=\\"arrow fa fa-window-maximize\\"/></a></div><block-child-1/><div class=\\"batch_slots\\"><block-child-2/><block-child-3/></div><div class=\\"batch_commits\\"><block-child-4/></div></div></div>\`);
   let block2 = createBlock(\`<i class=\\"fa fa-exclamation-triangle\\"/>\`);
@@ -34,7 +35,7 @@ exports[`misc complex template 1`] = `
     for (let i1 = 0; i1 < l_block4; i1++) {
       ctx[\`slot\`] = v_block4[i1];
       const key1 = ctx['slot'].id;
-      c_block4[i1] = withKey(component(\`SlotButton\`, {class: ctx['slot_container'], slot: ctx['slot']}, key + \`__1__\${key1}\`, node, ctx), key1);
+      c_block4[i1] = withKey(comp1({class: ctx['slot_container'],slot: ctx['slot']}, key + \`__1__\${key1}\`, node, this, null), key1);
     }
     ctx = ctx.__proto__;
     b4 = list(c_block4);
@@ -79,15 +80,15 @@ exports[`misc complex template 1`] = `
 `;
 
 exports[`misc global 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, zero, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`_callee-uses-foo\`);
-  const callTemplate_2 = getTemplate(\`_callee-uses-foo\`);
-  const callTemplate_3 = getTemplate(\`_callee-uses-foo\`);
-  const callTemplate_4 = getTemplate(\`_callee-asc\`);
-  const callTemplate_5 = getTemplate(\`_callee-asc-toto\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, zero, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`_callee-uses-foo\`);
+  const callTemplate_2 = app.getTemplate(\`_callee-uses-foo\`);
+  const callTemplate_3 = app.getTemplate(\`_callee-uses-foo\`);
+  const callTemplate_4 = app.getTemplate(\`_callee-asc\`);
+  const callTemplate_5 = app.getTemplate(\`_callee-asc-toto\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block4 = createBlock(\`<span><block-text-0/></span>\`);
@@ -131,9 +132,9 @@ exports[`misc global 1`] = `
 `;
 
 exports[`misc global 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { withDefault } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
@@ -146,9 +147,9 @@ exports[`misc global 2`] = `
 `;
 
 exports[`misc global 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<año block-attribute-0=\\"falló\\"><block-child-0/></año>\`);
@@ -162,29 +163,31 @@ exports[`misc global 3`] = `
 `;
 
 exports[`misc global 4`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { safeOutput, withDefault } = helpers;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     const b3 = text(\`toto default\`);
-    const b2 = withDefault(safeOutput(ctx['toto']), b3);
+    const b2 = safeOutput(ctx['toto'], b3);
     return block1([], [b2]);
   }
 }"
 `;
 
 exports[`misc other complex template 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, withKey, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`LOAD_INFOS_TEMPLATE\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`LOAD_INFOS_TEMPLATE\`);
+  const comp1 = app.createComponent(\`BundlesList\`, true, false, false, [\\"bundles\\",\\"category_custom_views\\",\\"search\\"]);
+  const comp2 = app.createComponent(\`BundlesList\`, true, false, false, [\\"bundles\\",\\"search\\"]);
   
-  let block1 = createBlock(\`<div><header><nav class=\\"navbar navbar-expand-md navbar-light bg-light\\"><a block-attribute-0=\\"href\\"><b style=\\"color:#777;\\"><block-text-1/></b></a><button type=\\"button\\" class=\\"navbar-toggler\\" data-toggle=\\"collapse\\" data-target=\\"#top_menu_collapse\\"><span class=\\"navbar-toggler-icon\\"/></button><div class=\\"collapse navbar-collapse\\" id=\\"top_menu_collapse\\" aria-expanded=\\"false\\"><ul class=\\"nav navbar-nav ml-auto text-right\\" id=\\"top_menu\\"><block-child-0/><li class=\\"nav-item divider\\"/><block-child-1/></ul><div><div class=\\"input-group input-group-sm\\"><div class=\\"input-group-prepend input-group-sm\\"><button class=\\"btn btn-default fa fa-cog\\" title=\\"Settings\\" block-handler-2=\\"click\\"/><button class=\\"btn btn-default\\" block-handler-3=\\"click\\"> More </button><block-child-2/></div><input class=\\"form-control\\" type=\\"text\\" placeholder=\\"Search\\" aria-label=\\"Search\\" name=\\"search\\" block-attribute-4=\\"value\\" block-handler-5=\\"keyup\\" block-handler-6=\\"change\\" block-ref=\\"7\\"/><div class=\\"input-group-append\\"><button class=\\"btn btn-default fa fa-eraser\\" block-handler-8=\\"click\\"/></div></div></div></div></nav></header><div class=\\"container-fluid\\" block-ref=\\"9\\"><div class=\\"row\\"><!--div class=\\"form-group col-md-6\\">
+  let block1 = createBlock(\`<div><header><nav class=\\"navbar navbar-expand-md navbar-light bg-light\\"><a block-attribute-0=\\"href\\"><b style=\\"color:#777;\\"><block-text-1/></b></a><button type=\\"button\\" class=\\"navbar-toggler\\" data-toggle=\\"collapse\\" data-target=\\"#top_menu_collapse\\"><span class=\\"navbar-toggler-icon\\"/></button><div class=\\"collapse navbar-collapse\\" id=\\"top_menu_collapse\\" aria-expanded=\\"false\\"><ul class=\\"nav navbar-nav ml-auto text-right\\" id=\\"top_menu\\"><block-child-0/><li class=\\"nav-item divider\\"/><block-child-1/></ul><div><div class=\\"input-group input-group-sm\\"><div class=\\"input-group-prepend input-group-sm\\"><button class=\\"btn btn-default fa fa-cog\\" title=\\"Settings\\" block-handler-2=\\"click\\"/><button class=\\"btn btn-default\\" block-handler-3=\\"click\\"> More </button><block-child-2/></div><input class=\\"form-control\\" type=\\"text\\" placeholder=\\"Search\\" aria-label=\\"Search\\" name=\\"search\\" block-property-4=\\"value\\" block-handler-5=\\"keyup\\" block-handler-6=\\"change\\" block-ref=\\"7\\"/><div class=\\"input-group-append\\"><button class=\\"btn btn-default fa fa-eraser\\" block-handler-8=\\"click\\"/></div></div></div></div></nav></header><div class=\\"container-fluid\\" block-ref=\\"9\\"><div class=\\"row\\"><!--div class=\\"form-group col-md-6\\">
                       <h5>Search options</h5>
                       <input class=\\"form-control\\" type=\\"text\\" name=\\"default_search\\" id=\\"default_search\\" t-att-checked=\\"default_search\\" placeholder=\\"Default search\\"/>
       
@@ -206,17 +209,14 @@ exports[`misc other complex template 1`] = `
   let block12 = createBlock(\`<li class=\\"nav-item divider\\"/>\`);
   let block13 = createBlock(\`<li class=\\"nav-item dropdown\\"><a href=\\"#\\" class=\\"nav-link dropdown-toggle\\" data-toggle=\\"dropdown\\"><b><span><block-text-0/></span></b></a><div class=\\"dropdown-menu js_usermenu\\" role=\\"menu\\"><a class=\\"dropdown-item\\" id=\\"o_logout\\" role=\\"menuitem\\" block-attribute-1=\\"href\\">Logout</a><a class=\\"dropdown-item\\" role=\\"menuitem\\" block-attribute-2=\\"href\\">Web</a></div></li>\`);
   let block14 = createBlock(\`<select class=\\"custom-select\\" name=\\"category\\" id=\\"category\\"><block-child-0/></select>\`);
-  let block16 = createBlock(\`<option block-attribute-0=\\"value\\" block-attribute-1=\\"selected\\"><block-text-2/></option>\`);
-  let block20 = createBlock(\`<div class=\\"form-check\\"><input class=\\"form-check-input\\" type=\\"checkbox\\" block-attribute-0=\\"name\\" block-attribute-1=\\"id\\" block-attribute-2=\\"checked\\" block-attribute-3=\\"data-trigger_id\\" block-handler-4=\\"change\\"/><label class=\\"form-check-label\\" block-attribute-5=\\"for\\"><block-text-6/></label></div>\`);
+  let block16 = createBlock(\`<option block-attribute-0=\\"value\\" block-property-1=\\"selected\\"><block-text-2/></option>\`);
+  let block20 = createBlock(\`<div class=\\"form-check\\"><input class=\\"form-check-input\\" type=\\"checkbox\\" block-attribute-0=\\"name\\" block-attribute-1=\\"id\\" block-property-2=\\"checked\\" block-attribute-3=\\"data-trigger_id\\" block-handler-4=\\"change\\"/><label class=\\"form-check-label\\" block-attribute-5=\\"for\\"><block-text-6/></label></div>\`);
   let block21 = createBlock(\`<div><button class=\\"btn btn-sm btn-default\\" block-handler-0=\\"click\\">All</button><button class=\\"btn btn-sm btn-default\\" block-handler-1=\\"click\\">None</button><button class=\\"btn btn-sm btn-info\\" block-handler-2=\\"click\\">Default</button><button class=\\"btn btn-sm btn-default\\" block-handler-3=\\"click\\">Close</button></div>\`);
   let block23 = createBlock(\`<div class=\\"alert alert-warning\\" role=\\"alert\\"><block-text-0/> <!-- todo fixme--></div>\`);
   let block24 = createBlock(\`<div class=\\"mb32\\"><h1>No project</h1></div>\`);
   let block25 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
-    const ref1 = (el) => refs[\`search_input\`] = el;
-    const ref2 = (el) => refs[\`settings_menu\`] = el;
     let b2,b4,b14,b17,b22,b23,b24,b25;
     let attr1 = \`/runbot/\${ctx['project'].slug}\`;
     let txt1 = ctx['project'].name;
@@ -266,18 +266,20 @@ exports[`misc other complex template 1`] = `
         ctx[\`category\`] = v_block15[i1];
         const key1 = ctx['category'].id;
         let attr6 = ctx['category'].id;
-        let attr7 = ctx['category'].id==ctx['options'].active_category_id;
+        let prop1 = new Boolean(ctx['category'].id==ctx['options'].active_category_id);
         let txt5 = ctx['category'].name;
-        c_block15[i1] = withKey(block16([attr6, attr7, txt5]), key1);
+        c_block15[i1] = withKey(block16([attr6, prop1, txt5]), key1);
       }
       ctx = ctx.__proto__;
       const b15 = list(c_block15);
       b14 = block14([], [b15]);
     }
-    let attr8 = ctx['search'].value;
+    let prop2 = new String((ctx['search'].value) === 0 ? 0 : ((ctx['search'].value) || \\"\\"));
     let hdlr4 = [ctx['updateFilter'], ctx];
     let hdlr5 = [ctx['updateFilter'], ctx];
+    let ref1 = (el) => this.__owl__.setRef((\`search_input\`), el);
     let hdlr6 = [ctx['clearSearch'], ctx];
+    let ref2 = (el) => this.__owl__.setRef((\`settings_menu\`), el);
     if (ctx['triggers']) {
       ctx = Object.create(ctx);
       const [k_block18, v_block18, l_block18, c_block18] = prepareList(ctx['triggers']);;
@@ -286,14 +288,14 @@ exports[`misc other complex template 1`] = `
         const key1 = ctx['trigger'].id;
         let b20;
         if (!ctx['trigger'].manual&&ctx['trigger'].project_id===ctx['project'].id&&ctx['trigger'].category_id===ctx['options'].active_category_id) {
-          let attr9 = \`trigger_\${ctx['trigger'].id}\`;
-          let attr10 = \`trigger_\${ctx['trigger'].id}\`;
-          let attr11 = ctx['options'].trigger_display[ctx['trigger'].id];
-          let attr12 = ctx['trigger'].id;
+          let attr7 = \`trigger_\${ctx['trigger'].id}\`;
+          let attr8 = \`trigger_\${ctx['trigger'].id}\`;
+          let prop3 = new Boolean(ctx['options'].trigger_display[ctx['trigger'].id]);
+          let attr9 = ctx['trigger'].id;
           let hdlr7 = [ctx['updateTriggerDisplay'], ctx];
-          let attr13 = \`trigger_\${ctx['trigger'].id}\`;
+          let attr10 = \`trigger_\${ctx['trigger'].id}\`;
           let txt6 = ctx['trigger'].name;
-          b20 = block20([attr9, attr10, attr11, attr12, hdlr7, attr13, txt6]);
+          b20 = block20([attr7, attr8, prop3, attr9, hdlr7, attr10, txt6]);
         }
         c_block18[i1] = withKey(multi([b20]), key1);
       }
@@ -316,11 +318,11 @@ exports[`misc other complex template 1`] = `
     if (!ctx['project']) {
       b24 = block24();
     } else {
-      const b26 = component(\`BundlesList\`, {bundles: ctx['bundles'].sticky, category_custom_views: ctx['category_custom_views'], search: ctx['search']}, key + \`__2\`, node, ctx);
-      const b27 = component(\`BundlesList\`, {bundles: ctx['bundles'].dev, search: ctx['search']}, key + \`__3\`, node, ctx);
+      const b26 = comp1({bundles: ctx['bundles'].sticky,category_custom_views: ctx['category_custom_views'],search: ctx['search']}, key + \`__2\`, node, this, null);
+      const b27 = comp2({bundles: ctx['bundles'].dev,search: ctx['search']}, key + \`__3\`, node, this, null);
       b25 = block25([], [b26, b27]);
     }
-    return block1([attr1, txt1, hdlr2, hdlr3, attr8, hdlr4, hdlr5, ref1, hdlr6, ref2], [b2, b4, b14, b17, b22, b23, b24, b25]);
+    return block1([attr1, txt1, hdlr2, hdlr3, prop2, hdlr4, hdlr5, ref1, hdlr6, ref2], [b2, b4, b14, b17, b22, b23, b24, b25]);
   }
 }"
 `;

tests/compiler/__snapshots__/properties.test.ts.snap

@@ -0,0 +1,250 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`changing an attribute with t-att- 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div block-attribute-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let attr1 = ctx['v'];
+    return block1([attr1]);
+  }
+}"
+`;
+
+exports[`dynamic input value: falsy values 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((0) === 0 ? 0 : ((0) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`dynamic input value: falsy values 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((false) === 0 ? 0 : ((false) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`dynamic input value: falsy values 3`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((undefined) === 0 ? 0 : ((undefined) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`dynamic input value: falsy values 4`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String(('') === 0 ? 0 : (('') || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`input of type checkbox with t-att-indeterminate 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input type=\\"checkbox\\" block-property-0=\\"indeterminate\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new Boolean(ctx['v']);
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`input type= checkbox, with t-att-checked 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input type=\\"checkbox\\" block-property-0=\\"checked\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new Boolean(ctx['flag']);
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`input with t-att-value (patching with same value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((ctx['v']) === 0 ? 0 : ((ctx['v']) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`input with t-att-value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((ctx['v']) === 0 ? 0 : ((ctx['v']) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`input, type checkbox, with t-att-checked (patching with same value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input type=\\"checkbox\\" block-property-0=\\"checked\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new Boolean(ctx['v']);
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`readonly and readOnly are both interpreted as the readOnly property 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input readonly=\\"\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
+exports[`readonly and readOnly are both interpreted as the readOnly property 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input readOnly=\\"\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
+exports[`readonly and readOnly are both interpreted as the readOnly property 3`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"readOnly\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new Boolean(ctx['val']);
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`readonly and readOnly are both interpreted as the readOnly property 4`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"readOnly\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new Boolean(ctx['val']);
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`select with t-att-value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<select block-property-0=\\"value\\"><option value=\\"potato\\">Potato</option><option value=\\"tomato\\">Tomato</option><option value=\\"onion\\">Onion</option></select>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((ctx['value']) === 0 ? 0 : ((ctx['value']) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`textarea with t-att-value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<textarea block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((ctx['v']) === 0 ? 0 : ((ctx['v']) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`updating property with falsy value 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<input block-property-0=\\"value\\"/>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let prop1 = new String((ctx['v']) === 0 ? 0 : ((ctx['v']) || \\"\\"));
+    return block1([prop1]);
+  }
+}"
+`;
+
+exports[`various boolean html attributes 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div><input type=\\"checkbox\\" checked=\\"checked\\"/><input checked=\\"checked\\"/><div checked=\\"checked\\"/><div selected=\\"selected\\"/><option selected=\\"selected\\" other=\\"1\\"/><input readonly=\\"readonly\\"/><button disabled=\\"disabled\\"/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;

tests/compiler/__snapshots__/qweb_memory.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`memory t-foreach does not leak stuff in global scope 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);

tests/compiler/__snapshots__/simple_templates.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`simple templates, mostly static can render a table row 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<tr><td>cell</td></tr>\`);
   
@@ -14,9 +14,9 @@ exports[`simple templates, mostly static can render a table row 1`] = `
 `;
 
 exports[`simple templates, mostly static div with a class attribute 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"abc\\">foo</div>\`);
   
@@ -27,9 +27,9 @@ exports[`simple templates, mostly static div with a class attribute 1`] = `
 `;
 
 exports[`simple templates, mostly static div with a class attribute with a quote 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div class=\\"a'bc\\">word</div>\`);
   
@@ -40,9 +40,9 @@ exports[`simple templates, mostly static div with a class attribute with a quote
 `;
 
 exports[`simple templates, mostly static div with a span child node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span>word</span></div>\`);
   
@@ -53,9 +53,9 @@ exports[`simple templates, mostly static div with a span child node 1`] = `
 `;
 
 exports[`simple templates, mostly static div with an arbitrary attribute with a quote 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div abc=\\"a'bc\\">word</div>\`);
   
@@ -66,9 +66,9 @@ exports[`simple templates, mostly static div with an arbitrary attribute with a
 `;
 
 exports[`simple templates, mostly static div with an empty class attribute 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>word</div>\`);
   
@@ -79,9 +79,9 @@ exports[`simple templates, mostly static div with an empty class attribute 1`] =
 `;
 
 exports[`simple templates, mostly static div with content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>foo</div>\`);
   
@@ -92,9 +92,9 @@ exports[`simple templates, mostly static div with content 1`] = `
 `;
 
 exports[`simple templates, mostly static dom node with t-esc 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -106,9 +106,9 @@ exports[`simple templates, mostly static dom node with t-esc 1`] = `
 `;
 
 exports[`simple templates, mostly static dom node with t-esc 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -120,9 +120,9 @@ exports[`simple templates, mostly static dom node with t-esc 2`] = `
 `;
 
 exports[`simple templates, mostly static dynamic text value 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['text']);
@@ -131,9 +131,9 @@ exports[`simple templates, mostly static dynamic text value 1`] = `
 `;
 
 exports[`simple templates, mostly static empty div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -144,9 +144,9 @@ exports[`simple templates, mostly static empty div 1`] = `
 `;
 
 exports[`simple templates, mostly static empty string 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`\`);
@@ -155,9 +155,9 @@ exports[`simple templates, mostly static empty string 1`] = `
 `;
 
 exports[`simple templates, mostly static empty string in a template set 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`\`);
@@ -166,9 +166,9 @@ exports[`simple templates, mostly static empty string in a template set 1`] = `
 `;
 
 exports[`simple templates, mostly static inline template string in t-esc 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`text\`);
@@ -177,9 +177,9 @@ exports[`simple templates, mostly static inline template string in t-esc 1`] = `
 `;
 
 exports[`simple templates, mostly static inline template string with content in t-esc 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -192,9 +192,9 @@ exports[`simple templates, mostly static inline template string with content in
 `;
 
 exports[`simple templates, mostly static inline template string with variable in context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`text \${ctx['v']}\`);
@@ -203,9 +203,9 @@ exports[`simple templates, mostly static inline template string with variable in
 `;
 
 exports[`simple templates, mostly static multiple root nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = createBlock(\`<div>foo</div>\`);
   let block3 = createBlock(\`<span>hey</span>\`);
@@ -219,9 +219,9 @@ exports[`simple templates, mostly static multiple root nodes 1`] = `
 `;
 
 exports[`simple templates, mostly static simple string 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`hello vdom\`);
@@ -230,9 +230,9 @@ exports[`simple templates, mostly static simple string 1`] = `
 `;
 
 exports[`simple templates, mostly static simple string in t tag 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`hello vdom\`);
@@ -241,9 +241,9 @@ exports[`simple templates, mostly static simple string in t tag 1`] = `
 `;
 
 exports[`simple templates, mostly static static text and dynamic text (no t tag) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(\`hello \`);
@@ -254,9 +254,9 @@ exports[`simple templates, mostly static static text and dynamic text (no t tag)
 `;
 
 exports[`simple templates, mostly static static text and dynamic text 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(\`hello \`);
@@ -267,9 +267,9 @@ exports[`simple templates, mostly static static text and dynamic text 1`] = `
 `;
 
 exports[`simple templates, mostly static t-esc in dom node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -281,9 +281,9 @@ exports[`simple templates, mostly static t-esc in dom node 1`] = `
 `;
 
 exports[`simple templates, mostly static t-esc in dom node, variations 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>hello <block-text-0/></div>\`);
   
@@ -295,9 +295,9 @@ exports[`simple templates, mostly static t-esc in dom node, variations 1`] = `
 `;
 
 exports[`simple templates, mostly static t-esc in dom node, variations 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>hello <block-text-0/> world</div>\`);
   
@@ -309,9 +309,9 @@ exports[`simple templates, mostly static t-esc in dom node, variations 2`] = `
 `;
 
 exports[`simple templates, mostly static template with multiple t tag with multiple content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/>Loading<block-text-2/></div>\`);
   
@@ -325,9 +325,9 @@ exports[`simple templates, mostly static template with multiple t tag with multi
 `;
 
 exports[`simple templates, mostly static template with t tag with multiple content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>Loading<block-child-0/></div>\`);
   
@@ -342,9 +342,9 @@ exports[`simple templates, mostly static template with t tag with multiple conte
 `;
 
 exports[`simple templates, mostly static two t-escs next to each other 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(ctx['text1']);
@@ -355,9 +355,9 @@ exports[`simple templates, mostly static two t-escs next to each other 1`] = `
 `;
 
 exports[`simple templates, mostly static two t-escs next to each other 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(ctx['text1']);
@@ -368,9 +368,9 @@ exports[`simple templates, mostly static two t-escs next to each other 2`] = `
 `;
 
 exports[`simple templates, mostly static two t-escs next to each other, in a div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
   

tests/compiler/__snapshots__/svg.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`properly support svg add proper namespace to g tags 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<g block-ns=\\"http://www.w3.org/2000/svg\\"><circle cx=\\"50\\" cy=\\"50\\" r=\\"4\\" stroke=\\"green\\" stroke-width=\\"1\\" fill=\\"yellow\\"/> </g>\`);
   
@@ -14,9 +14,9 @@ exports[`properly support svg add proper namespace to g tags 1`] = `
 `;
 
 exports[`properly support svg add proper namespace to svg 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\" width=\\"100px\\" height=\\"90px\\"><circle cx=\\"50\\" cy=\\"50\\" r=\\"4\\" stroke=\\"green\\" stroke-width=\\"1\\" fill=\\"yellow\\"/> </svg>\`);
   
@@ -27,9 +27,9 @@ exports[`properly support svg add proper namespace to svg 1`] = `
 `;
 
 exports[`properly support svg namespace to g tags not added if already in svg namespace 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><g/></svg>\`);
   
@@ -40,9 +40,9 @@ exports[`properly support svg namespace to g tags not added if already in svg na
 `;
 
 exports[`properly support svg namespace to svg tags added even if already in svg namespace 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><svg/></svg>\`);
   
@@ -53,9 +53,9 @@ exports[`properly support svg namespace to svg tags added even if already in svg
 `;
 
 exports[`properly support svg svg creates new block if it is within html -- 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><polygon fill=\\"#000000\\" points=\\"0 0 4 4 8 0\\" transform=\\"translate(5 7)\\"/><block-child-0/></svg>\`);
@@ -73,9 +73,9 @@ exports[`properly support svg svg creates new block if it is within html -- 2 1`
 `;
 
 exports[`properly support svg svg creates new block if it is within html 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><polygon fill=\\"#000000\\" points=\\"0 0 4 4 8 0\\" transform=\\"translate(5 7)\\"/></svg>\`);
@@ -88,11 +88,10 @@ exports[`properly support svg svg creates new block if it is within html 1`] = `
 `;
 
 exports[`properly support svg svg namespace added to sub templates if root tag is path 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`path\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`path\`);
   
   let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><block-child-0/></svg>\`);
   
@@ -104,9 +103,9 @@ exports[`properly support svg svg namespace added to sub templates if root tag i
 `;
 
 exports[`properly support svg svg namespace added to sub templates if root tag is path 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<path block-ns=\\"http://www.w3.org/2000/svg\\"/>\`);
   
@@ -117,9 +116,9 @@ exports[`properly support svg svg namespace added to sub templates if root tag i
 `;
 
 exports[`properly support svg svg namespace added to sub-blocks 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<svg block-ns=\\"http://www.w3.org/2000/svg\\"><block-child-0/></svg>\`);
   let block2 = createBlock(\`<path block-ns=\\"http://www.w3.org/2000/svg\\"/>\`);

tests/compiler/__snapshots__/t_call.test.ts.snap

@@ -1,11 +1,10 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-call (template calling) basic caller 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`_basic-callee\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`_basic-callee\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -17,9 +16,9 @@ exports[`t-call (template calling) basic caller 1`] = `
 `;
 
 exports[`t-call (template calling) basic caller 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -30,11 +29,10 @@ exports[`t-call (template calling) basic caller 2`] = `
 `;
 
 exports[`t-call (template calling) basic caller, no parent node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`_basic-callee\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`_basic-callee\`);
   
   return function template(ctx, node, key = \\"\\") {
     return callTemplate_1.call(this, ctx, node, key + \`__1\`);
@@ -43,9 +41,9 @@ exports[`t-call (template calling) basic caller, no parent node 1`] = `
 `;
 
 exports[`t-call (template calling) basic caller, no parent node 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -56,11 +54,11 @@ exports[`t-call (template calling) basic caller, no parent node 2`] = `
 `;
 
 exports[`t-call (template calling) call with several sub nodes on same line 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>hey</span>\`);
@@ -81,9 +79,9 @@ exports[`t-call (template calling) call with several sub nodes on same line 1`]
 `;
 
 exports[`t-call (template calling) call with several sub nodes on same line 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -96,11 +94,11 @@ exports[`t-call (template calling) call with several sub nodes on same line 2`]
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0' 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`subTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`subTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>hey</span>\`);
@@ -121,11 +119,11 @@ exports[`t-call (template calling) cascading t-call t-out='0' 1`] = `
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0' 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`subSubTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`subSubTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>cascade 0</span>\`);
@@ -144,11 +142,11 @@ exports[`t-call (template calling) cascading t-call t-out='0' 2`] = `
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0' 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`finalTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`finalTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>cascade 1</span>\`);
@@ -167,9 +165,9 @@ exports[`t-call (template calling) cascading t-call t-out='0' 3`] = `
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0' 4`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<div><span>cascade 2</span><block-child-0/></div>\`);
@@ -182,11 +180,11 @@ exports[`t-call (template calling) cascading t-call t-out='0' 4`] = `
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0', without external divs 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`subTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`subTemplate\`);
   
   let block2 = createBlock(\`<span>hey</span>\`);
   let block4 = createBlock(\`<span>yay</span>\`);
@@ -205,11 +203,11 @@ exports[`t-call (template calling) cascading t-call t-out='0', without external
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0', without external divs 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`subSubTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`subSubTemplate\`);
   
   let block2 = createBlock(\`<span>cascade 0</span>\`);
   
@@ -226,11 +224,11 @@ exports[`t-call (template calling) cascading t-call t-out='0', without external
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0', without external divs 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`finalTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`finalTemplate\`);
   
   let block2 = createBlock(\`<span>cascade 1</span>\`);
   
@@ -247,9 +245,9 @@ exports[`t-call (template calling) cascading t-call t-out='0', without external
 `;
 
 exports[`t-call (template calling) cascading t-call t-out='0', without external divs 4`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block2 = createBlock(\`<span>cascade 2</span>\`);
@@ -263,10 +261,10 @@ exports[`t-call (template calling) cascading t-call t-out='0', without external
 `;
 
 exports[`t-call (template calling) dynamic t-call 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { call } = helpers;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const call = app.callTemplate.bind(app);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -279,9 +277,9 @@ exports[`t-call (template calling) dynamic t-call 1`] = `
 `;
 
 exports[`t-call (template calling) dynamic t-call 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<foo><block-text-0/></foo>\`);
   
@@ -293,9 +291,9 @@ exports[`t-call (template calling) dynamic t-call 2`] = `
 `;
 
 exports[`t-call (template calling) dynamic t-call 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<bar><block-text-0/></bar>\`);
   
@@ -307,11 +305,11 @@ exports[`t-call (template calling) dynamic t-call 3`] = `
 `;
 
 exports[`t-call (template calling) inherit context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -326,9 +324,9 @@ exports[`t-call (template calling) inherit context 1`] = `
 `;
 
 exports[`t-call (template calling) inherit context 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);
@@ -336,12 +334,62 @@ exports[`t-call (template calling) inherit context 2`] = `
 }"
 `;
 
-exports[`t-call (template calling) recursive template, part 1 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-call (template calling) nested t-calls with magic variable 0 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`recursive\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`grandchild\`);
+  const callTemplate_2 = app.getTemplate(\`child\`);
+  
+  let block1 = createBlock(\`<p>Some content...</p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
+    const b1 = block1();
+    ctx[zero] = b1;
+    const b2 = callTemplate_1.call(this, ctx, node, key + \`__1\`);
+    ctx = ctx.__proto__;
+    ctx[zero] = b2;
+    return callTemplate_2.call(this, ctx, node, key + \`__2\`);
+  }
+}"
+`;
+
+exports[`t-call (template calling) nested t-calls with magic variable 0 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { zero } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    const b2 = text(\`grandchild\`);
+    const b3 = ctx[zero];
+    return multi([b2, b3]);
+  }
+}"
+`;
+
+exports[`t-call (template calling) nested t-calls with magic variable 0 3`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { zero } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return ctx[zero];
+  }
+}"
+`;
+
+exports[`t-call (template calling) recursive template, part 1 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`recursive\`);
   
   let block1 = createBlock(\`<div><span>hey</span><block-child-0/></div>\`);
   
@@ -356,11 +404,11 @@ exports[`t-call (template calling) recursive template, part 1 1`] = `
 `;
 
 exports[`t-call (template calling) recursive template, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -377,11 +425,11 @@ exports[`t-call (template calling) recursive template, part 2 1`] = `
 `;
 
 exports[`t-call (template calling) recursive template, part 2 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/></div>\`);
   
@@ -411,11 +459,11 @@ exports[`t-call (template calling) recursive template, part 2 2`] = `
 `;
 
 exports[`t-call (template calling) recursive template, part 3 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -432,11 +480,11 @@ exports[`t-call (template calling) recursive template, part 3 1`] = `
 `;
 
 exports[`t-call (template calling) recursive template, part 3 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/></div>\`);
   
@@ -466,11 +514,11 @@ exports[`t-call (template calling) recursive template, part 3 2`] = `
 `;
 
 exports[`t-call (template calling) recursive template, part 4: with t-set recursive index 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -488,11 +536,11 @@ exports[`t-call (template calling) recursive template, part 4: with t-set recurs
 `;
 
 exports[`t-call (template calling) recursive template, part 4: with t-set recursive index 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, prepareList, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`nodeTemplate\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue, prepareList, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/> <block-text-1/></p><block-child-0/></div>\`);
   
@@ -524,11 +572,11 @@ exports[`t-call (template calling) recursive template, part 4: with t-set recurs
 `;
 
 exports[`t-call (template calling) scoped parameters 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   
@@ -547,9 +595,9 @@ exports[`t-call (template calling) scoped parameters 1`] = `
 `;
 
 exports[`t-call (template calling) scoped parameters 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`ok\`);
@@ -558,11 +606,11 @@ exports[`t-call (template calling) scoped parameters 2`] = `
 `;
 
 exports[`t-call (template calling) scoped parameters, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   
@@ -582,9 +630,9 @@ exports[`t-call (template calling) scoped parameters, part 2 1`] = `
 `;
 
 exports[`t-call (template calling) scoped parameters, part 2 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);
@@ -593,11 +641,10 @@ exports[`t-call (template calling) scoped parameters, part 2 2`] = `
 `;
 
 exports[`t-call (template calling) t-call allowed on a non t node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -609,9 +656,9 @@ exports[`t-call (template calling) t-call allowed on a non t node 1`] = `
 `;
 
 exports[`t-call (template calling) t-call allowed on a non t node 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -621,12 +668,42 @@ exports[`t-call (template calling) t-call allowed on a non t node 2`] = `
 }"
 `;
 
-exports[`t-call (template calling) t-call with body content as root of a template 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-call (template calling) t-call on a div with t-call-context 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`antony\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
+  
+  let block1 = createBlock(\`<div><block-child-0/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let ctx1 = ctx['obj'];
+    const b2 = callTemplate_1.call(this, ctx1, node, key + \`__1\`);
+    return block1([], [b2]);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-call on a div with t-call-context 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<span><block-text-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let txt1 = ctx['value'];
+    return block1([txt1]);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-call with body content as root of a template 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`antony\`);
   
   let block1 = createBlock(\`<p>antony</p>\`);
   
@@ -641,9 +718,9 @@ exports[`t-call (template calling) t-call with body content as root of a templat
 `;
 
 exports[`t-call (template calling) t-call with body content as root of a template 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<foo><block-child-0/></foo>\`);
@@ -656,11 +733,10 @@ exports[`t-call (template calling) t-call with body content as root of a templat
 `;
 
 exports[`t-call (template calling) t-call with t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -675,9 +751,9 @@ exports[`t-call (template calling) t-call with t-if 1`] = `
 `;
 
 exports[`t-call (template calling) t-call with t-if 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -688,11 +764,11 @@ exports[`t-call (template calling) t-call with t-if 2`] = `
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and body text content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -709,9 +785,9 @@ exports[`t-call (template calling) t-call with t-set inside and body text conten
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and body text content 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -723,11 +799,11 @@ exports[`t-call (template calling) t-call with t-set inside and body text conten
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and outside 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -757,9 +833,9 @@ exports[`t-call (template calling) t-call with t-set inside and outside 1`] = `
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and outside 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -771,11 +847,11 @@ exports[`t-call (template calling) t-call with t-set inside and outside 2`] = `
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and outside. 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`main\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`main\`);
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -790,11 +866,11 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 1`] =
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and outside. 2 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -824,9 +900,9 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 2`] =
 `;
 
 exports[`t-call (template calling) t-call with t-set inside and outside. 2 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -840,12 +916,12 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 3`] =
 `;
 
 exports[`t-call (template calling) t-call, conditional and t-set in t-call body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`callee1\`);
-  const callTemplate_2 = getTemplate(\`callee2\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`callee1\`);
+  const callTemplate_2 = app.getTemplate(\`callee2\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -869,9 +945,9 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 `;
 
 exports[`t-call (template calling) t-call, conditional and t-set in t-call body 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>callee1</div>\`);
   
@@ -882,9 +958,9 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 `;
 
 exports[`t-call (template calling) t-call, conditional and t-set in t-call body 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>callee2 <block-text-0/></div>\`);
   
@@ -895,12 +971,73 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 }"
 `;
 
-exports[`t-call (template calling) t-esc inside t-call, with t-set outside 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-call (template calling) t-call-context 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let ctx1 = ctx['obj'];
+    return callTemplate_1.call(this, ctx1, node, key + \`__1\`);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-call-context 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<span><block-text-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let txt1 = ctx['value'];
+    return block1([txt1]);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-call-context and value in body 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let ctx1 = ctx['obj'];
+    ctx1 = Object.create(ctx1);
+    ctx1[isBoundary] = 1;
+    setContextValue(ctx1, \\"value2\\", ctx['aaron']);
+    return callTemplate_1.call(this, ctx1, node, key + \`__1\`);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-call-context and value in body 2`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    let txt1 = ctx['value1'];
+    let txt2 = ctx['value2'];
+    return block1([txt1, txt2]);
+  }
+}"
+`;
+
+exports[`t-call (template calling) t-esc inside t-call, with t-set outside 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -915,9 +1052,9 @@ exports[`t-call (template calling) t-esc inside t-call, with t-set outside 1`] =
 `;
 
 exports[`t-call (template calling) t-esc inside t-call, with t-set outside 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -929,11 +1066,11 @@ exports[`t-call (template calling) t-esc inside t-call, with t-set outside 2`] =
 `;
 
 exports[`t-call (template calling) with unused body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -946,9 +1083,9 @@ exports[`t-call (template calling) with unused body 1`] = `
 `;
 
 exports[`t-call (template calling) with unused body 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>ok</div>\`);
   
@@ -959,11 +1096,11 @@ exports[`t-call (template calling) with unused body 2`] = `
 `;
 
 exports[`t-call (template calling) with unused setbody 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -977,9 +1114,9 @@ exports[`t-call (template calling) with unused setbody 1`] = `
 `;
 
 exports[`t-call (template calling) with unused setbody 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>ok</div>\`);
   
@@ -990,11 +1127,11 @@ exports[`t-call (template calling) with unused setbody 2`] = `
 `;
 
 exports[`t-call (template calling) with used body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -1007,9 +1144,9 @@ exports[`t-call (template calling) with used body 1`] = `
 `;
 
 exports[`t-call (template calling) with used body 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<h1><block-text-0/></h1>\`);
@@ -1022,11 +1159,11 @@ exports[`t-call (template calling) with used body 2`] = `
 `;
 
 exports[`t-call (template calling) with used setbody 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1043,9 +1180,9 @@ exports[`t-call (template calling) with used setbody 1`] = `
 `;
 
 exports[`t-call (template calling) with used setbody 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);

tests/compiler/__snapshots__/t_debug_log.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`debugging t-debug 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>hey</span>\`);
@@ -21,9 +21,9 @@ exports[`debugging t-debug 1`] = `
 `;
 
 exports[`debugging t-debug on sub template 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<p>coucou</p>\`);
   
@@ -35,11 +35,10 @@ exports[`debugging t-debug on sub template 1`] = `
 `;
 
 exports[`debugging t-debug on sub template 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -51,9 +50,9 @@ exports[`debugging t-debug on sub template 2`] = `
 `;
 
 exports[`debugging t-log 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);

tests/compiler/__snapshots__/t_esc.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-esc div with falsy values 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><p><block-text-1/></p><p><block-text-2/></p><p><block-text-3/></p><p><block-text-4/></p></div>\`);
   
@@ -19,9 +19,9 @@ exports[`t-esc div with falsy values 1`] = `
 `;
 
 exports[`t-esc escaping 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -33,9 +33,9 @@ exports[`t-esc escaping 1`] = `
 `;
 
 exports[`t-esc escaping on a node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -47,9 +47,9 @@ exports[`t-esc escaping on a node 1`] = `
 `;
 
 exports[`t-esc escaping on a node with a body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { withDefault } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
@@ -62,9 +62,9 @@ exports[`t-esc escaping on a node with a body 1`] = `
 `;
 
 exports[`t-esc escaping on a node with a body, as a default 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { withDefault } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
@@ -77,9 +77,9 @@ exports[`t-esc escaping on a node with a body, as a default 1`] = `
 `;
 
 exports[`t-esc falsy values in text nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(ctx['v1']);
@@ -97,9 +97,9 @@ exports[`t-esc falsy values in text nodes 1`] = `
 `;
 
 exports[`t-esc literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -111,9 +111,9 @@ exports[`t-esc literal 1`] = `
 `;
 
 exports[`t-esc t-esc is escaped 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -126,7 +126,32 @@ exports[`t-esc t-esc is escaped 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`var\`] = new LazyValue(value1, ctx, node);
+    ctx[\`var\`] = new LazyValue(value1, ctx, this, node, key);
+    let txt1 = ctx['var'];
+    return block1([txt1]);
+  }
+}"
+`;
+
+exports[`t-esc t-esc with the 0 number 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['var']);
+  }
+}"
+`;
+
+exports[`t-esc t-esc with the 0 number, in a p 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<p><block-text-0/></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
     let txt1 = ctx['var'];
     return block1([txt1]);
   }
@@ -134,9 +159,9 @@ exports[`t-esc t-esc is escaped 1`] = `
 `;
 
 exports[`t-esc t-esc work with spread operator 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -148,11 +173,11 @@ exports[`t-esc t-esc work with spread operator 1`] = `
 `;
 
 exports[`t-esc t-esc=0 is escaped 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<p>escaped</p>\`);
@@ -169,9 +194,9 @@ exports[`t-esc t-esc=0 is escaped 1`] = `
 `;
 
 exports[`t-esc t-esc=0 is escaped 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
@@ -183,10 +208,21 @@ exports[`t-esc t-esc=0 is escaped 2`] = `
 }"
 `;
 
-exports[`t-esc variable 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-esc top level t-esc with undefined 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return text(ctx['var']);
+  }
+}"
+`;
+
+exports[`t-esc variable 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   

tests/compiler/__snapshots__/t_foreach.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-foreach does not pollute the rendering context 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -23,9 +23,9 @@ exports[`t-foreach does not pollute the rendering context 1`] = `
 `;
 
 exports[`t-foreach iterate on items (on a element node) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -47,9 +47,9 @@ exports[`t-foreach iterate on items (on a element node) 1`] = `
 `;
 
 exports[`t-foreach iterate on items 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -78,9 +78,9 @@ exports[`t-foreach iterate on items 1`] = `
 `;
 
 exports[`t-foreach iterate, dict param 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -109,9 +109,9 @@ exports[`t-foreach iterate, dict param 1`] = `
 `;
 
 exports[`t-foreach iterate, position 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -145,9 +145,9 @@ exports[`t-foreach iterate, position 1`] = `
 `;
 
 exports[`t-foreach simple iteration (in a node) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -167,9 +167,9 @@ exports[`t-foreach simple iteration (in a node) 1`] = `
 `;
 
 exports[`t-foreach simple iteration 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -186,9 +186,9 @@ exports[`t-foreach simple iteration 1`] = `
 `;
 
 exports[`t-foreach simple iteration with two nodes inside 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block3 = createBlock(\`<span>a<block-text-0/></span>\`);
@@ -212,11 +212,11 @@ exports[`t-foreach simple iteration with two nodes inside 1`] = `
 `;
 
 exports[`t-foreach t-call with body in t-foreach in t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, isBoundary, withDefault, setContextValue, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, isBoundary, withDefault, setContextValue, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><span>[<block-text-0/>][<block-text-1/>][<block-text-2/>]</span></div>\`);
   let block6 = createBlock(\`<span><block-text-0/></span>\`);
@@ -265,9 +265,9 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 1`] = `
 `;
 
 exports[`t-foreach t-call with body in t-foreach in t-foreach 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     const b2 = text(\` [\`);
@@ -283,11 +283,11 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 2`] = `
 `;
 
 exports[`t-foreach t-call without body in t-foreach in t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { prepareList, getTemplate, withKey } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { prepareList, withKey } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><span>[<block-text-0/>][<block-text-1/>][<block-text-2/>]</span></div>\`);
   let block6 = createBlock(\`<span><block-text-0/></span>\`);
@@ -330,9 +330,9 @@ exports[`t-foreach t-call without body in t-foreach in t-foreach 1`] = `
 `;
 
 exports[`t-foreach t-call without body in t-foreach in t-foreach 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -352,9 +352,9 @@ exports[`t-foreach t-call without body in t-foreach in t-foreach 2`] = `
 `;
 
 exports[`t-foreach t-foreach in t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -386,9 +386,9 @@ exports[`t-foreach t-foreach in t-foreach 1`] = `
 `;
 
 exports[`t-foreach t-foreach with t-if inside (no external node) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block3 = createBlock(\`<span><block-text-0/></span>\`);
@@ -412,9 +412,9 @@ exports[`t-foreach t-foreach with t-if inside (no external node) 1`] = `
 `;
 
 exports[`t-foreach t-foreach with t-if inside 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -440,9 +440,9 @@ exports[`t-foreach t-foreach with t-if inside 1`] = `
 `;
 
 exports[`t-foreach t-key on t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -463,9 +463,9 @@ exports[`t-foreach t-key on t-foreach 1`] = `
 `;
 
 exports[`t-foreach throws error if invalid loop expression 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -488,9 +488,9 @@ exports[`t-foreach throws error if invalid loop expression 1`] = `
 `;
 
 exports[`t-foreach with t-memo 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);

tests/compiler/__snapshots__/t_if.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-if a t-if next to a div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = createBlock(\`<div>foo</div>\`);
   
@@ -19,9 +19,9 @@ exports[`t-if a t-if next to a div 1`] = `
 `;
 
 exports[`t-if a t-if with two inner nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block3 = createBlock(\`<span>yip</span>\`);
   let block4 = createBlock(\`<div>yip</div>\`);
@@ -39,9 +39,9 @@ exports[`t-if a t-if with two inner nodes 1`] = `
 `;
 
 exports[`t-if boolean value condition elif (no outside node) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3,b4,b5;
@@ -60,9 +60,9 @@ exports[`t-if boolean value condition elif (no outside node) 1`] = `
 `;
 
 exports[`t-if boolean value condition elif 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/><block-child-2/><block-child-3/></div>\`);
   
@@ -83,9 +83,9 @@ exports[`t-if boolean value condition elif 1`] = `
 `;
 
 exports[`t-if boolean value condition else 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span>begin</span><block-child-0/><block-child-1/><span>end</span></div>\`);
   
@@ -102,9 +102,9 @@ exports[`t-if boolean value condition else 1`] = `
 `;
 
 exports[`t-if boolean value condition false else 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span>begin</span><block-child-0/><block-child-1/><span>end</span></div>\`);
   
@@ -121,9 +121,9 @@ exports[`t-if boolean value condition false else 1`] = `
 `;
 
 exports[`t-if boolean value condition missing 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -138,9 +138,9 @@ exports[`t-if boolean value condition missing 1`] = `
 `;
 
 exports[`t-if can use some boolean operators in expressions 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/><block-child-2/><block-child-3/><block-child-4/><block-child-5/><block-child-6/><block-child-7/></div>\`);
   
@@ -176,9 +176,9 @@ exports[`t-if can use some boolean operators in expressions 1`] = `
 `;
 
 exports[`t-if div containing a t-if with two inner nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>yip</span>\`);
@@ -197,9 +197,9 @@ exports[`t-if div containing a t-if with two inner nodes 1`] = `
 `;
 
 exports[`t-if dynamic content after t-if with two children nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   let block3 = createBlock(\`<p>1</p>\`);
@@ -219,9 +219,9 @@ exports[`t-if dynamic content after t-if with two children nodes 1`] = `
 `;
 
 exports[`t-if just a t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -234,9 +234,9 @@ exports[`t-if just a t-if 1`] = `
 `;
 
 exports[`t-if simple t-if/t-else 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -251,9 +251,9 @@ exports[`t-if simple t-if/t-else 1`] = `
 `;
 
 exports[`t-if simple t-if/t-else in a div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -270,9 +270,9 @@ exports[`t-if simple t-if/t-else in a div 1`] = `
 `;
 
 exports[`t-if t-esc with t-elif 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -289,9 +289,9 @@ exports[`t-if t-esc with t-elif 1`] = `
 `;
 
 exports[`t-if t-esc with t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -306,9 +306,9 @@ exports[`t-if t-esc with t-if 1`] = `
 `;
 
 exports[`t-if t-if and t-else with two nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block4 = createBlock(\`<span>a</span>\`);
   let block5 = createBlock(\`<span>b</span>\`);
@@ -328,9 +328,9 @@ exports[`t-if t-if and t-else with two nodes 1`] = `
 `;
 
 exports[`t-if t-if in a div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -345,9 +345,9 @@ exports[`t-if t-if in a div 1`] = `
 `;
 
 exports[`t-if t-if in a t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>1<block-child-0/></span>\`);
@@ -367,9 +367,9 @@ exports[`t-if t-if in a t-if 1`] = `
 `;
 
 exports[`t-if t-if with empty content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -383,9 +383,9 @@ exports[`t-if t-if with empty content 1`] = `
 `;
 
 exports[`t-if t-if/t-else with more content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -402,9 +402,9 @@ exports[`t-if t-if/t-else with more content 1`] = `
 `;
 
 exports[`t-if t-set, then t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -423,9 +423,9 @@ exports[`t-if t-set, then t-if 1`] = `
 `;
 
 exports[`t-if t-set, then t-if, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -446,9 +446,9 @@ exports[`t-if t-set, then t-if, part 2 1`] = `
 `;
 
 exports[`t-if t-set, then t-if, part 3 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
@@ -472,9 +472,9 @@ exports[`t-if t-set, then t-if, part 3 1`] = `
 `;
 
 exports[`t-if two consecutive t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -490,9 +490,9 @@ exports[`t-if two consecutive t-if 1`] = `
 `;
 
 exports[`t-if two consecutive t-if in a div 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -510,9 +510,9 @@ exports[`t-if two consecutive t-if in a div 1`] = `
 `;
 
 exports[`t-if two t-ifs next to each other 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span><block-text-0/></span>\`);

tests/compiler/__snapshots__/t_key.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-key can use t-key directive on a node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -16,9 +16,9 @@ exports[`t-key can use t-key directive on a node 1`] = `
 `;
 
 exports[`t-key can use t-key directive on a node 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -31,9 +31,9 @@ exports[`t-key can use t-key directive on a node 2 1`] = `
 `;
 
 exports[`t-key can use t-key directive on a node as a function 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -46,9 +46,9 @@ exports[`t-key can use t-key directive on a node as a function 1`] = `
 `;
 
 exports[`t-key t-key directive in a list 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<ul><block-child-0/></ul>\`);
@@ -70,9 +70,9 @@ exports[`t-key t-key directive in a list 1`] = `
 `;
 
 exports[`t-key t-key on sub dom node pushes a child block in its parent 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span/>\`);
@@ -91,9 +91,9 @@ exports[`t-key t-key on sub dom node pushes a child block in its parent 1`] = `
 `;
 
 exports[`t-key t-key on sub dom node pushes a child block in its parent 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><h1/></div>\`);
   

tests/compiler/__snapshots__/t_out.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-out literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -16,9 +16,9 @@ exports[`t-out literal 1`] = `
 `;
 
 exports[`t-out literal, no outside html element 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -28,11 +28,11 @@ exports[`t-out literal, no outside html element 1`] = `
 `;
 
 exports[`t-out multiple calls to t-out 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>coucou</span>\`);
@@ -49,9 +49,9 @@ exports[`t-out multiple calls to t-out 1`] = `
 `;
 
 exports[`t-out multiple calls to t-out 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><div>Greeter</div><block-child-1/></div>\`);
@@ -65,9 +65,9 @@ exports[`t-out multiple calls to t-out 2`] = `
 `;
 
 exports[`t-out not escaping 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -79,12 +79,27 @@ exports[`t-out not escaping 1`] = `
 }"
 `;
 
-exports[`t-out t-out 0 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-out number literal 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, zero, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`_basic-callee\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
+  
+  let block1 = createBlock(\`<span><block-child-0/></span>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    const b2 = safeOutput(1);
+    return block1([], [b2]);
+  }
+}"
+`;
+
+exports[`t-out t-out 0 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, zero } = helpers;
+  const callTemplate_1 = app.getTemplate(\`_basic-callee\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<div>zero</div>\`);
@@ -101,9 +116,9 @@ exports[`t-out t-out 0 1`] = `
 `;
 
 exports[`t-out t-out 0 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { zero } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -116,9 +131,9 @@ exports[`t-out t-out 0 2`] = `
 `;
 
 exports[`t-out t-out and another sibling node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><span>hello</span><block-child-0/></span>\`);
@@ -131,9 +146,9 @@ exports[`t-out t-out and another sibling node 1`] = `
 `;
 
 exports[`t-out t-out bdom 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue, safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><span><block-child-0/></span></div>\`);
@@ -146,7 +161,7 @@ exports[`t-out t-out bdom 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`var\`] = new LazyValue(value1, ctx, node);
+    ctx[\`var\`] = new LazyValue(value1, ctx, this, node, key);
     const b3 = safeOutput(ctx['var']);
     return block1([], [b3]);
   }
@@ -154,9 +169,9 @@ exports[`t-out t-out bdom 1`] = `
 `;
 
 exports[`t-out t-out block 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -169,9 +184,9 @@ exports[`t-out t-out block 1`] = `
 `;
 
 exports[`t-out t-out escaped 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -184,9 +199,9 @@ exports[`t-out t-out escaped 1`] = `
 `;
 
 exports[`t-out t-out markedup 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -199,42 +214,42 @@ exports[`t-out t-out markedup 1`] = `
 `;
 
 exports[`t-out t-out on a node with a body, as a default 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { safeOutput, withDefault } = helpers;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     const b3 = text(\`nope\`);
-    const b2 = withDefault(safeOutput(ctx['var']), b3);
+    const b2 = safeOutput(ctx['var'], b3);
     return block1([], [b2]);
   }
 }"
 `;
 
 exports[`t-out t-out on a node with a dom node in body, as a default 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { safeOutput, withDefault } = helpers;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   let block3 = createBlock(\`<div>nope</div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     const b3 = block3();
-    const b2 = withDefault(safeOutput(ctx['var']), b3);
+    const b2 = safeOutput(ctx['var'], b3);
     return block1([], [b2]);
   }
 }"
 `;
 
 exports[`t-out t-out switch escaped 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -247,9 +262,9 @@ exports[`t-out t-out switch escaped 1`] = `
 `;
 
 exports[`t-out t-out switch escaped on markup 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -262,9 +277,9 @@ exports[`t-out t-out switch escaped on markup 1`] = `
 `;
 
 exports[`t-out t-out switch markup 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -277,9 +292,9 @@ exports[`t-out t-out switch markup 1`] = `
 `;
 
 exports[`t-out t-out switch markup on bdom 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue, safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
@@ -295,7 +310,7 @@ exports[`t-out t-out switch markup on bdom 1`] = `
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
     let b3,b5;
-    ctx[\`bdom\`] = new LazyValue(value1, ctx, node);
+    ctx[\`bdom\`] = new LazyValue(value1, ctx, this, node, key);
     if (ctx['hasBdom']) {
       const b4 = safeOutput(ctx['bdom']);
       b3 = block3([], [b4]);
@@ -309,9 +324,9 @@ exports[`t-out t-out switch markup on bdom 1`] = `
 `;
 
 exports[`t-out t-out switch markup on escaped 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -324,9 +339,9 @@ exports[`t-out t-out switch markup on escaped 1`] = `
 `;
 
 exports[`t-out t-out with a <t/> in body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -336,9 +351,9 @@ exports[`t-out t-out with a <t/> in body 1`] = `
 `;
 
 exports[`t-out t-out with arbitrary object 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -351,9 +366,9 @@ exports[`t-out t-out with arbitrary object 1`] = `
 `;
 
 exports[`t-out t-out with arbitrary object 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -366,9 +381,9 @@ exports[`t-out t-out with arbitrary object 2 1`] = `
 `;
 
 exports[`t-out t-out with comment 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -381,9 +396,48 @@ exports[`t-out t-out with comment 1`] = `
 `;
 
 exports[`t-out t-out with just a t-set t-value in body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return safeOutput(ctx['var']);
+  }
+}"
+`;
+
+exports[`t-out t-out with the 0 number 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
+  
+  return function template(ctx, node, key = \\"\\") {
+    return safeOutput(ctx['var']);
+  }
+}"
+`;
+
+exports[`t-out t-out with the 0 number, in a p 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { safeOutput } = helpers;
+  
+  let block1 = createBlock(\`<p><block-child-0/></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    const b2 = safeOutput(ctx['var']);
+    return block1([], [b2]);
+  }
+}"
+`;
+
+exports[`t-out top level t-out with undefined 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -393,9 +447,9 @@ exports[`t-out t-out with just a t-set t-value in body 1`] = `
 `;
 
 exports[`t-out variable 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -408,9 +462,9 @@ exports[`t-out variable 1`] = `
 `;
 
 exports[`t-out with a String class 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -423,9 +477,9 @@ exports[`t-out with a String class 1`] = `
 `;
 
 exports[`t-out with an extended String class 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
@@ -438,9 +492,9 @@ exports[`t-out with an extended String class 1`] = `
 `;
 
 exports[`t-raw is deprecated should warn 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -453,9 +507,9 @@ exports[`t-raw is deprecated should warn 1`] = `
 `;
 
 exports[`t-raw is deprecated t-out is actually called in t-raw's place 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);

tests/compiler/__snapshots__/t_ref.test.ts.snap

@@ -1,42 +1,54 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-ref can get a dynamic ref on a node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span block-ref=\\"0\\"/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
     const v1 = ctx['id'];
-    let ref1 = (el) => refs[\`myspan\${v1}\`] = el;
+    let ref1 = (el) => this.__owl__.setRef((\`myspan\${v1}\`), el);
+    return block1([ref1]);
+  }
+}"
+`;
+
+exports[`t-ref can get a dynamic ref on a node, alternate syntax 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div><span block-ref=\\"0\\"/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    const v1 = ctx['id'];
+    let ref1 = (el) => this.__owl__.setRef((\`myspan\${v1}\`), el);
     return block1([ref1]);
   }
 }"
 `;
 
 exports[`t-ref can get a ref on a node 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span block-ref=\\"0\\"/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
-    const ref1 = (el) => refs[\`myspan\`] = el;
+    let ref1 = (el) => this.__owl__.setRef((\`myspan\`), el);
     return block1([ref1]);
   }
 }"
 `;
 
 exports[`t-ref ref in a t-call 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -48,33 +60,31 @@ exports[`t-ref ref in a t-call 1`] = `
 `;
 
 exports[`t-ref ref in a t-call 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>1<span block-ref=\\"0\\"/>2</div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
-    const ref1 = (el) => refs[\`name\`] = el;
+    let ref1 = (el) => this.__owl__.setRef((\`name\`), el);
     return block1([ref1]);
   }
 }"
 `;
 
 exports[`t-ref ref in a t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span block-ref=\\"0\\"/>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
-    const ref1 = (el) => refs[\`name\`] = el;
     let b2;
     if (ctx['condition']) {
+      let ref1 = (el) => this.__owl__.setRef((\`name\`), el);
       b2 = block2([ref1]);
     }
     return block1([], [b2]);
@@ -83,16 +93,15 @@ exports[`t-ref ref in a t-if 1`] = `
 `;
 
 exports[`t-ref refs in a loop 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div block-ref=\\"0\\"><block-text-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['items']);;
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -100,7 +109,7 @@ exports[`t-ref refs in a loop 1`] = `
       const key1 = ctx['item'];
       const tKey_1 = ctx['item'];
       const v1 = ctx['item'];
-      let ref1 = (el) => refs[\`\${v1}\`] = el;
+      let ref1 = (el) => this.__owl__.setRef(((v1)), el);
       let txt1 = ctx['item'];
       c_block2[i1] = withKey(block3([ref1, txt1]), tKey_1 + key1);
     }
@@ -111,21 +120,20 @@ exports[`t-ref refs in a loop 1`] = `
 `;
 
 exports[`t-ref two refs, one in a t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-child-0/><p block-ref=\\"0\\"/></div>\`);
   let block2 = createBlock(\`<span block-ref=\\"0\\"/>\`);
   
   return function template(ctx, node, key = \\"\\") {
-    const refs = ctx.__owl__.refs;
-    const ref1 = (el) => refs[\`name\`] = el;
-    const ref2 = (el) => refs[\`p\`] = el;
     let b2;
     if (ctx['condition']) {
+      let ref1 = (el) => this.__owl__.setRef((\`name\`), el);
       b2 = block2([ref1]);
     }
+    let ref2 = (el) => this.__owl__.setRef((\`p\`), el);
     return block1([ref2], [b2]);
   }
 }"

tests/compiler/__snapshots__/t_set.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`t-set evaluate value expression 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -19,9 +19,9 @@ exports[`t-set evaluate value expression 1`] = `
 `;
 
 exports[`t-set evaluate value expression, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -37,9 +37,9 @@ exports[`t-set evaluate value expression, part 2 1`] = `
 `;
 
 exports[`t-set set from attribute literal (no outside div) 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -52,9 +52,9 @@ exports[`t-set set from attribute literal (no outside div) 1`] = `
 `;
 
 exports[`t-set set from attribute literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -70,9 +70,9 @@ exports[`t-set set from attribute literal 1`] = `
 `;
 
 exports[`t-set set from attribute lookup 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -88,9 +88,9 @@ exports[`t-set set from attribute lookup 1`] = `
 `;
 
 exports[`t-set set from body literal (with t-if/t-else 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue } = helpers;
   
   function value1(ctx, node, key = \\"\\") {
@@ -106,16 +106,16 @@ exports[`t-set set from body literal (with t-if/t-else 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`value\`] = new LazyValue(value1, ctx, node);
+    ctx[\`value\`] = new LazyValue(value1, ctx, this, node, key);
     return text(ctx['value']);
   }
 }"
 `;
 
 exports[`t-set set from body literal 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -128,9 +128,9 @@ exports[`t-set set from body literal 1`] = `
 `;
 
 exports[`t-set set from body lookup 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -142,7 +142,7 @@ exports[`t-set set from body lookup 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`stuff\`] = new LazyValue(value1, ctx, node);
+    ctx[\`stuff\`] = new LazyValue(value1, ctx, this, node, key);
     let txt1 = ctx['stuff'];
     return block1([txt1]);
   }
@@ -150,9 +150,9 @@ exports[`t-set set from body lookup 1`] = `
 `;
 
 exports[`t-set set from empty body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -168,9 +168,9 @@ exports[`t-set set from empty body 1`] = `
 `;
 
 exports[`t-set t-set and t-if 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -189,9 +189,9 @@ exports[`t-set t-set and t-if 1`] = `
 `;
 
 exports[`t-set t-set body is evaluated immediately 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, LazyValue, safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -206,7 +206,7 @@ exports[`t-set t-set body is evaluated immediately 1`] = `
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
     setContextValue(ctx, \\"v1\\", 'before');
-    ctx[\`v2\`] = new LazyValue(value1, ctx, node);
+    ctx[\`v2\`] = new LazyValue(value1, ctx, this, node, key);
     setContextValue(ctx, \\"v1\\", 'after');
     const b3 = safeOutput(ctx['v2']);
     return block1([], [b3]);
@@ -215,11 +215,11 @@ exports[`t-set t-set body is evaluated immediately 1`] = `
 `;
 
 exports[`t-set t-set can't alter from within callee 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
   
@@ -236,9 +236,9 @@ exports[`t-set t-set can't alter from within callee 1`] = `
 `;
 
 exports[`t-set t-set can't alter from within callee 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
@@ -255,11 +255,11 @@ exports[`t-set t-set can't alter from within callee 2`] = `
 `;
 
 exports[`t-set t-set can't alter in t-call body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { isBoundary, withDefault, setContextValue, getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`sub\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  const callTemplate_1 = app.getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
   
@@ -280,9 +280,9 @@ exports[`t-set t-set can't alter in t-call body 1`] = `
 `;
 
 exports[`t-set t-set can't alter in t-call body 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
@@ -299,9 +299,9 @@ exports[`t-set t-set can't alter in t-call body 2`] = `
 `;
 
 exports[`t-set t-set does not modify render context existing key values 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -317,9 +317,9 @@ exports[`t-set t-set does not modify render context existing key values 1`] = `
 `;
 
 exports[`t-set t-set evaluates an expression only once 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
@@ -336,9 +336,9 @@ exports[`t-set t-set evaluates an expression only once 1`] = `
 `;
 
 exports[`t-set t-set outside modified in t-foreach 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
@@ -366,9 +366,9 @@ exports[`t-set t-set outside modified in t-foreach 1`] = `
 `;
 
 exports[`t-set t-set outside modified in t-foreach increment-after operator 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
@@ -396,9 +396,9 @@ exports[`t-set t-set outside modified in t-foreach increment-after operator 1`]
 `;
 
 exports[`t-set t-set outside modified in t-foreach increment-before operator 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
@@ -426,9 +426,9 @@ exports[`t-set t-set outside modified in t-foreach increment-before operator 1`]
 `;
 
 exports[`t-set t-set should reuse variable if possible 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, prepareList, withKey } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -455,9 +455,9 @@ exports[`t-set t-set should reuse variable if possible 1`] = `
 `;
 
 exports[`t-set t-set with content and sub t-esc 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -471,7 +471,7 @@ exports[`t-set t-set with content and sub t-esc 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`setvar\`] = new LazyValue(value1, ctx, node);
+    ctx[\`setvar\`] = new LazyValue(value1, ctx, this, node, key);
     let txt1 = ctx['setvar'];
     return block1([txt1]);
   }
@@ -479,9 +479,9 @@ exports[`t-set t-set with content and sub t-esc 1`] = `
 `;
 
 exports[`t-set t-set with t-value (falsy) and body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, LazyValue, safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -497,7 +497,7 @@ exports[`t-set t-set with t-value (falsy) and body 1`] = `
     ctx[isBoundary] = 1
     setContextValue(ctx, \\"v3\\", false);
     setContextValue(ctx, \\"v1\\", 'before');
-    ctx[\`v2\`] = withDefault(ctx['v3'], new LazyValue(value1, ctx, node));
+    ctx[\`v2\`] = withDefault(ctx['v3'], new LazyValue(value1, ctx, this, node, key));
     setContextValue(ctx, \\"v1\\", 'after');
     setContextValue(ctx, \\"v3\\", true);
     const b3 = safeOutput(ctx['v2']);
@@ -507,9 +507,9 @@ exports[`t-set t-set with t-value (falsy) and body 1`] = `
 `;
 
 exports[`t-set t-set with t-value (truthy) and body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue, LazyValue, safeOutput } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -525,7 +525,7 @@ exports[`t-set t-set with t-value (truthy) and body 1`] = `
     ctx[isBoundary] = 1
     setContextValue(ctx, \\"v3\\", 'Truthy');
     setContextValue(ctx, \\"v1\\", 'before');
-    ctx[\`v2\`] = withDefault(ctx['v3'], new LazyValue(value1, ctx, node));
+    ctx[\`v2\`] = withDefault(ctx['v3'], new LazyValue(value1, ctx, this, node, key));
     setContextValue(ctx, \\"v1\\", 'after');
     setContextValue(ctx, \\"v3\\", false);
     const b3 = safeOutput(ctx['v2']);
@@ -534,13 +534,36 @@ exports[`t-set t-set with t-value (truthy) and body 1`] = `
 }"
 `;
 
-exports[`t-set t-set, t-if, and mix of expression/body lookup, 1 1`] = `
-"function anonymous(bdom, helpers
+exports[`t-set t-set, multiple t-ifs, and a specific configuration 1`] = `
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
-  let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-text-0/></div>\`);
+  let block1 = createBlock(\`<p><div><span>First div</span></div><div><block-child-0/></div></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let b2;
+    if (ctx['flag']) {
+      setContextValue(ctx, \\"bouh\\", 2);
+    }
+    if (!ctx['flag']) {
+      b2 = text(\`Second\`);
+    }
+    return block1([], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set, t-if, and mix of expression/body lookup, 1 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  let { isBoundary, withDefault, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -557,12 +580,12 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 1 1`] = `
 `;
 
 exports[`t-set t-set, t-if, and mix of expression/body lookup, 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
-  let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-text-0/></div>\`);
+  let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -579,9 +602,9 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 2 1`] = `
 `;
 
 exports[`t-set t-set, t-if, and mix of expression/body lookup, 3 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
@@ -600,9 +623,9 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 3 1`] = `
 `;
 
 exports[`t-set value priority (with non text body 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, LazyValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
@@ -615,7 +638,7 @@ exports[`t-set value priority (with non text body 1`] = `
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
     ctx[isBoundary] = 1
-    ctx[\`value\`] = withDefault(1, new LazyValue(value1, ctx, node));
+    ctx[\`value\`] = withDefault(1, new LazyValue(value1, ctx, this, node, key));
     let txt1 = ctx['value'];
     return block1([txt1]);
   }
@@ -623,9 +646,9 @@ exports[`t-set value priority (with non text body 1`] = `
 `;
 
 exports[`t-set value priority 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   let { isBoundary, withDefault, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);

tests/compiler/__snapshots__/t_tag.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`qweb t-tag can fallback if falsy tag 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 'fallback'}/>\`);
   
@@ -15,9 +15,9 @@ exports[`qweb t-tag can fallback if falsy tag 1`] = `
 `;
 
 exports[`qweb t-tag can update 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'}/>\`);
   
@@ -29,9 +29,9 @@ exports[`qweb t-tag can update 1`] = `
 `;
 
 exports[`qweb t-tag simple usecases 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'}/>\`);
   
@@ -43,9 +43,9 @@ exports[`qweb t-tag simple usecases 1`] = `
 `;
 
 exports[`qweb t-tag simple usecases 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'}>text</\${tag || 't'}>\`);
   
@@ -57,9 +57,9 @@ exports[`qweb t-tag simple usecases 2`] = `
 `;
 
 exports[`qweb t-tag with multiple attributes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'} class=\\"blueberry\\" taste=\\"raspberry\\">gooseberry</\${tag || 't'}>\`);
   
@@ -71,9 +71,9 @@ exports[`qweb t-tag with multiple attributes 1`] = `
 `;
 
 exports[`qweb t-tag with multiple child nodes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'}> pear <span>apple</span> strawberry </\${tag || 't'}>\`);
   
@@ -85,9 +85,9 @@ exports[`qweb t-tag with multiple child nodes 1`] = `
 `;
 
 exports[`qweb t-tag with multiple t-tag in same template 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = tag => createBlock(\`<\${tag || 't'}><block-child-0/></\${tag || 't'}>\`);
   let block2 = tag => createBlock(\`<\${tag || 't'}>baz</\${tag || 't'}>\`);
@@ -102,9 +102,9 @@ exports[`qweb t-tag with multiple t-tag in same template 1`] = `
 `;
 
 exports[`qweb t-tag with multiple t-tag in same template, part 2 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = tag => createBlock(\`<\${tag || 't'}>bar</\${tag || 't'}>\`);
   let block3 = tag => createBlock(\`<\${tag || 't'}>baz</\${tag || 't'}>\`);

tests/compiler/__snapshots__/template_set.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`loading templates addTemplates does not modify its xml document in place 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -15,9 +15,9 @@ exports[`loading templates addTemplates does not modify its xml document in plac
 `;
 
 exports[`loading templates can initialize qweb with a string 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>jupiler</div>\`);
   
@@ -28,9 +28,9 @@ exports[`loading templates can initialize qweb with a string 1`] = `
 `;
 
 exports[`loading templates can initialize qweb with an XMLDocument 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>jupiler</div>\`);
   
@@ -41,11 +41,10 @@ exports[`loading templates can initialize qweb with an XMLDocument 1`] = `
 `;
 
 exports[`loading templates can load a few templates from a xml string 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`items\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`items\`);
   
   let block1 = createBlock(\`<ul><block-child-0/></ul>\`);
   
@@ -57,9 +56,9 @@ exports[`loading templates can load a few templates from a xml string 1`] = `
 `;
 
 exports[`loading templates can load a few templates from a xml string 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = createBlock(\`<li>ok</li>\`);
   let block3 = createBlock(\`<li>foo</li>\`);
@@ -73,11 +72,10 @@ exports[`loading templates can load a few templates from a xml string 2`] = `
 `;
 
 exports[`loading templates can load a few templates from an XMLDocument 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
-  let { getTemplate } = helpers;
-  const callTemplate_1 = getTemplate(\`items\`);
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  const callTemplate_1 = app.getTemplate(\`items\`);
   
   let block1 = createBlock(\`<ul><block-child-0/></ul>\`);
   
@@ -89,9 +87,9 @@ exports[`loading templates can load a few templates from an XMLDocument 1`] = `
 `;
 
 exports[`loading templates can load a few templates from an XMLDocument 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block2 = createBlock(\`<li>ok</li>\`);
   let block3 = createBlock(\`<li>foo</li>\`);

tests/compiler/__snapshots__/translation.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`translation support can set and remove translatable attributes 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div tomato=\\"word\\" potato=\\"mot\\" title=\\"mot\\" label=\\"word\\">text</div>\`);
   
@@ -14,9 +14,9 @@ exports[`translation support can set and remove translatable attributes 1`] = `
 `;
 
 exports[`translation support can translate node content 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div>mot</div>\`);
   
@@ -27,9 +27,9 @@ exports[`translation support can translate node content 1`] = `
 `;
 
 exports[`translation support does not translate node content if disabled 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span>mot</span><span>word</span></div>\`);
   
@@ -40,9 +40,9 @@ exports[`translation support does not translate node content if disabled 1`] = `
 `;
 
 exports[`translation support some attributes are translated 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><p label=\\"mot\\">mot</p><p title=\\"mot\\">mot</p><p placeholder=\\"mot\\">mot</p><p alt=\\"mot\\">mot</p><p something=\\"word\\">mot</p></div>\`);
   
@@ -53,9 +53,9 @@ exports[`translation support some attributes are translated 1`] = `
 `;
 
 exports[`translation support translation is done on the trimmed text, with extra spaces readded after 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div> mot </div>\`);
   
@@ -64,3 +64,16 @@ exports[`translation support translation is done on the trimmed text, with extra
   }
 }"
 `;
+
+exports[`translation support translation works, even if initial string has inner consecutive white space 1`] = `
+"function anonymous(app, bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
+  
+  let block1 = createBlock(\`<div>un mot</div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;

tests/compiler/__snapshots__/white_space.test.ts.snap

@@ -1,9 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`white space handling consecutives whitespaces are condensed into a single space 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div> abc </div>\`);
   
@@ -14,9 +14,9 @@ exports[`white space handling consecutives whitespaces are condensed into a sing
 `;
 
 exports[`white space handling nothing is done in pre tags 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<pre>   </pre>\`);
   
@@ -27,9 +27,9 @@ exports[`white space handling nothing is done in pre tags 1`] = `
 `;
 
 exports[`white space handling nothing is done in pre tags 2`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<pre>
           some text
@@ -42,9 +42,9 @@ exports[`white space handling nothing is done in pre tags 2`] = `
 `;
 
 exports[`white space handling nothing is done in pre tags 3`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<pre>
           
@@ -57,9 +57,9 @@ exports[`white space handling nothing is done in pre tags 3`] = `
 `;
 
 exports[`white space handling pre inside a div with a new line 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><pre>SomeText</pre></div>\`);
   
@@ -70,9 +70,9 @@ exports[`white space handling pre inside a div with a new line 1`] = `
 `;
 
 exports[`white space handling white space only text nodes are condensed into a single space 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div> </div>\`);
   
@@ -83,9 +83,9 @@ exports[`white space handling white space only text nodes are condensed into a s
 `;
 
 exports[`white space handling whitespace only text nodes with newlines are removed 1`] = `
-"function anonymous(bdom, helpers
+"function anonymous(app, bdom, helpers
 ) {
-  let { text, createBlock, list, multi, html, toggler, component, comment } = bdom;
+  let { text, createBlock, list, multi, html, toggler, comment } = bdom;
   
   let block1 = createBlock(\`<div><span>abc</span></div>\`);
   

tests/compiler/attributes.test.ts

@@ -1,4 +1,4 @@
-import { mount, patch } from "../../src/blockdom";
+import { mount, patch } from "../../src/runtime/blockdom";
 import { makeTestFixture, renderToBdom, renderToString, snapshotEverything } from "../helpers";
 
 snapshotEverything();
@@ -12,6 +12,11 @@ describe("attributes", () => {
     expect(renderToString(template)).toBe(`<div foo="a" bar="b" baz="c"></div>`);
   });
 
+  test("static attributes with backslash or backtick", () => {
+    const template = `<div foo="\\a" bar="\\n" baz="\`"/>`;
+    expect(renderToString(template)).toBe(`<div foo="\\a" bar="\\n" baz="\`"></div>`);
+  });
+
   test("two classes", () => {
     const template = `<div class="a b"/>`;
     expect(renderToString(template)).toBe(`<div class="a b"></div>`);
@@ -22,6 +27,12 @@ describe("attributes", () => {
     expect(renderToString(template)).toBe(`<div aria-label="Close"></div>`);
   });
 
+  test("static attributes with backticks", () => {
+    const template = '<div foo="`bar`"></div>';
+    const result = renderToString(template);
+    expect(result).toBe('<div foo="`bar`"></div>');
+  });
+
   test("static attributes on void elements", () => {
     const template = `<img src="/test.skip.jpg" alt="Test"/>`;
     expect(renderToString(template)).toBe(`<img src="/test.skip.jpg" alt="Test">`);
@@ -33,6 +44,12 @@ describe("attributes", () => {
     expect(result).toBe(`<div foo="bar"></div>`);
   });
 
+  test("dynamic attributes with backticks", () => {
+    const template = '<div t-att-foo="`bar`"/>';
+    const result = renderToString(template);
+    expect(result).toBe(`<div foo="bar"></div>`);
+  });
+
   test("two dynamic attributes", () => {
     const template = `<div t-att-foo="'bar'" t-att-bar="'foo'"/>`;
     const result = renderToString(template);
@@ -51,6 +68,24 @@ describe("attributes", () => {
     expect(result).toBe(`<div></div>`);
   });
 
+  test("dynamic class attribute which is only a space", () => {
+    const template = `<div t-att-class="c"/>`;
+    const result = renderToString(template, { c: " " });
+    expect(result).toBe(`<div></div>`);
+  });
+
+  test("dynamic class attribute with multiple consecutive spaces", () => {
+    const template = `<div t-att-class="c"/>`;
+    const result = renderToString(template, { c: "a  b" });
+    expect(result).toBe(`<div class="a b"></div>`);
+  });
+
+  test("dynamic class attribute that starts and ends with a space", () => {
+    const template = `<div t-att-class="c"/>`;
+    const result = renderToString(template, { c: " a " });
+    expect(result).toBe(`<div class="a"></div>`);
+  });
+
   test("dynamic undefined generic attribute", () => {
     const template = `<div t-att-thing="c"/>`;
     const result = renderToString(template, { c: undefined });
@@ -131,6 +166,12 @@ describe("attributes", () => {
     expect(result).toBe(`<div foo="bar"></div>`);
   });
 
+  test("string interpolation, alternate syntax", () => {
+    const template = `<div t-attf-foo="b#{value}r"/>`;
+    const result = renderToString(template, { value: "a" });
+    expect(result).toBe(`<div foo="bar"></div>`);
+  });
+
   test("t-attf-class", () => {
     const template = `<div t-attf-class="hello"/>`;
     const result = renderToString(template);
@@ -242,6 +283,14 @@ describe("attributes", () => {
     const template = `<div class="static" t-att-class="{a: b, c: d, e: f}"/>`;
     const result = renderToString(template, { b: true, d: false, f: true });
     expect(result).toBe(`<div class="static a e"></div>`);
+    // leading and trailing space in the key
+    expect(renderToString(`<div t-att-class="{' a ': value}" />`, { value: true })).toBe(
+      '<div class="a"></div>'
+    );
+    // whitespace only key
+    expect(renderToString(`<div t-att-class="{' ': value}" />`, { value: true })).toBe(
+      "<div></div>"
+    );
   });
 
   test("t-att-class with multiple classes", () => {
@@ -251,6 +300,10 @@ describe("attributes", () => {
     expect(renderToString(`<div t-att-class="{['a b c']: value}" />`, { value: true })).toBe(
       '<div class="a b c"></div>'
     );
+    // multiple spaces between classes
+    expect(renderToString(`<div t-att-class="{'a  b  c': value}" />`, { value: true })).toBe(
+      '<div class="a b c"></div>'
+    );
   });
 
   test("t-att-class with multiple classes, some of which are duplicate", () => {
@@ -262,25 +315,6 @@ describe("attributes", () => {
     ).toBe('<div class="a b d"></div>');
   });
 
-  test("changing an attribute with t-att-", () => {
-    // render input with initial value
-    const template = `<div t-att-value="v"/>`;
-    const bnode1 = renderToBdom(template, { v: "zucchini" });
-    const fixture = makeTestFixture();
-    mount(bnode1, fixture);
-
-    expect(fixture.innerHTML).toBe('<div value="zucchini"></div>');
-
-    const bnode2 = renderToBdom(template, { v: "potato" });
-    patch(bnode1, bnode2);
-    expect(fixture.innerHTML).toBe('<div value="potato"></div>');
-
-    const bnode3 = renderToBdom(template, { v: "" });
-    patch(bnode1, bnode3);
-    // not sure about this. maybe we want to remove the attribute?
-    expect(fixture.innerHTML).toBe('<div value=""></div>');
-  });
-
   test("changing a class with t-att-class", () => {
     // render input with initial value
     const template = `<div t-att-class="v"/>`;
@@ -338,98 +372,3 @@ describe("attributes", () => {
     expect(fixture.innerHTML).toBe('<div class="hoy a b"></div>');
   });
 });
-
-describe("special cases for some specific html attributes/properties", () => {
-  test("input type= checkbox, with t-att-checked", () => {
-    const template = `<input type="checkbox" t-att-checked="flag"/>`;
-    const result = renderToString(template, { flag: true });
-    expect(result).toBe(`<input type="checkbox">`);
-  });
-
-  test("various boolean html attributes", () => {
-    // will cause the template to be snapshotted
-    renderToString(`
-      <div>
-        <input type="checkbox" checked="checked"/>
-        <input checked="checked"/>
-        <div checked="checked"/>
-        <div selected="selected"/>
-        <option selected="selected" other="1"/>
-        <input readonly="readonly"/>
-        <button disabled="disabled"/>
-      </div>
-      `);
-  });
-
-  test("input with t-att-value", () => {
-    // render input with initial value
-    const template = `<input  t-att-value="v"/>`;
-    const bnode1 = renderToBdom(template, { v: "zucchini" });
-    const fixture = makeTestFixture();
-    mount(bnode1, fixture);
-    const input = fixture.querySelector("input")!;
-    expect(input.value).toBe("zucchini");
-
-    // change value manually in input, to simulate user input
-    input.value = "tomato";
-    expect(input.value).toBe("tomato");
-
-    // rerender with a different value, and patch actual dom, to check that
-    // input value was properly reset by owl
-    const bnode2 = renderToBdom(template, { v: "potato" });
-    patch(bnode1, bnode2);
-    expect(input.value).toBe("potato");
-  });
-
-  test("input of type checkbox with t-att-indeterminate", () => {
-    const template = `<input type="checkbox" t-att-indeterminate="v"/>`;
-    const bnode1 = renderToBdom(template, { v: true });
-    const fixture = makeTestFixture();
-    mount(bnode1, fixture);
-    const input = fixture.querySelector("input")!;
-    expect(input.indeterminate).toBe(true);
-  });
-
-  test("textarea with t-att-value", () => {
-    // render textarea with initial value
-    const template = `<textarea t-att-value="v"/>`;
-    const bnode1 = renderToBdom(template, { v: "zucchini" });
-    const fixture = makeTestFixture();
-    mount(bnode1, fixture);
-    const elm = fixture.querySelector("textarea")!;
-    expect(elm.value).toBe("zucchini");
-
-    // change value manually in textarea, to simulate user textarea
-    elm.value = "tomato";
-    expect(elm.value).toBe("tomato");
-
-    // rerender with a different value, and patch actual dom, to check that
-    // textarea value was properly reset by owl
-    const bnode2 = renderToBdom(template, { v: "potato" });
-    patch(bnode1, bnode2);
-    expect(elm.value).toBe("potato");
-  });
-
-  test("select with t-att-value", () => {
-    const template = `
-      <select t-att-value="value">
-        <option value="potato">Potato</option>
-        <option value="tomato">Tomato</option>
-        <option value="onion">Onion</option>
-      </select>`;
-    const bnode1 = renderToBdom(template, { value: "tomato" });
-    const fixture = makeTestFixture();
-    mount(bnode1, fixture);
-    const elm = fixture.querySelector("select")!;
-    expect(elm.value).toBe("tomato");
-
-    elm.value = "potato";
-    expect(elm.value).toBe("potato");
-
-    // rerender with a different value, and patch actual dom, to check that
-    // select value was properly reset by owl
-    const bnode2 = renderToBdom(template, { value: "onion" });
-    patch(bnode1, bnode2);
-    expect(elm.value).toBe("onion");
-  });
-});